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 .lA, 
 
 Reprinted from The Journal of Comparative Psycholoqt 
 Vol. II, No. 2, April, 1922 
 
 FATIGUE EFFECTS AS MEASURED BY SUGAR 
 CONTENT OF BLOOD^ 
 
 BUFORD J. JOHNSON 
 
 From the Bureau of Educational Experiments, New York City 
 
 The purpose of this investigation was the study of changes in 
 the sugar content of the blood of children as related to different 
 kinds and amounts of activity. Observations of children in the 
 performance of varied activities indicate the need of other criteria 
 of fatigue than diminished capacity or decrease in output in a 
 given activity within a given period of time. In some cases the 
 stimulating factors in the situation lead to a continued output that 
 is relatively good, though the effort expended would indicate the 
 presence of fatigue. In other cases the decrease in output is 
 greater but the assumption that there is greater fatigue present 
 does not seem justified. The intensity of the stimulus to ac- 
 tivity is doubtless conditioning the output and interfering with 
 such a form of fatigue test. The tendency to combat the onset 
 of fatigue by exaggerated activity is often noted. This leads to 
 speeding up or spurts and also to a slowing up and increased 
 tension or force in movements. With repetition of the activities 
 at short intervals the behavior of individuals tends to fall into 
 types which emphasize the preceding assumptions. 
 
 There is lack of uniformity among investigators concerning the 
 change in sugar content of the blood under continuous working 
 conditions. That a slight but steady increase may occur in the 
 rate at which adrenalin enters the circulation during exercise is 
 held by some writers. Schneider and Havens (1) report an 
 increase in the output of adrenalin with the onset of muscular 
 activity. Cannon (2) holds that adrenalin is secreted under the 
 stimulatory effects of anticipation, enters the blood stream, and 
 
 ^ A briefer report of this investigation was made at the meeting of the American 
 Psychological Association in Princeton, December, 1921. 
 
 y 155
 
 156 
 
 BUFORD J. JOHNSON 
 
 increases the functional capacity of muscles. He reports glyco- 
 suria after muscular exercise and also after scholarship examina- 
 tions as evidence of increased sugar content of blood. Stewart 
 and Rogoff (3) found that external manifestations of emotional 
 excitement and presumably, therefore, the visceral concomitants 
 of emotion could be evoked in a perfectly normal manner in 
 animals whose suprarenal glands have been isolated from the 
 central nervous system. Bainbridge (4) reviews the experimental 
 evidence and concludes that the share taken by adrenalin in 
 bringing about the circulatory and other changes taking place 
 during exercise, even when this is carried out under emotional 
 stress, is comparatively small. In a study of the blood of dogs 
 during exercise, Scott and Hastings (5) found that the concen- 
 tration of sugar falls steadily throughout the work period. Bro- 
 samlen and Sterkel (6) assert that the contradictory statements 
 concerning the change in sugar content of the blood that occurs 
 after muscular exercise are due to variations in interval between 
 end of work and determination of blood sugar value. They made 
 determinations before and after exercise, then followed this latter 
 determination by four others made at intervals varying from forty 
 minutes to one hour and twenty minutes. The following data 
 for healthy adults from their study show the irregularity as to 
 decrease or increase in sugar content immediately after exercise. 
 
 IMDITIDU AL 
 
 AGE 
 
 TIME OF 
 
 FIRST 
 DETERMI- 
 NATION 
 
 FIRST 
 
 SUGAR 
 
 CONTENT 
 
 TIME 
 WORK 
 ENDED 
 
 TIME OP 
 SECOND 
 DETERMI- 
 NATION 
 
 SECOND 
 
 SUGAR 
 
 CONTENT 
 
 VARIATION 
 
 
 
 0. m. 
 
 
 a. m. 
 
 0. m. 
 
 
 
 A. 
 
 24 
 
 7:00 
 
 0.086 
 
 7:40 
 
 7:50 
 
 0.082 
 
 -4 
 
 B. 
 
 26 
 
 7:20 
 
 0.093 
 
 8:05 
 
 8:20 
 
 0.085 
 
 -8 
 
 C. 
 
 33 
 
 7:05 
 
 0.088 
 
 7:50 
 
 8:20 
 
 0.102 
 
 +14 
 
 D. 
 
 27 
 
 7:10 
 
 0.078 
 
 7:50 
 
 8:20 
 
 0.074 
 
 -4 
 
 E. 
 
 32 
 
 6:20 
 
 0.096 
 
 6:50 
 
 7:00 
 
 0.104 
 
 +8 
 
 F. 
 
 22 
 
 6:20 
 
 0.094 
 
 7:00 
 
 7:10 
 
 0.082 
 
 -12 
 
 G. 
 
 18 
 
 7:20 
 
 0.076 
 
 8:05 
 
 8:20 
 
 0.087 
 
 +11 
 
 H. 
 
 40 
 
 7:10 
 
 0.082 
 
 8:05 
 
 8:20 
 
 0.082 
 
 
 
 I. 
 
 28 
 
 7:10 
 
 0.092 
 
 7:55 
 
 8:05 
 
 0.087 
 
 -5 
 
 J. 
 
 21 
 
 7:00 
 
 0.082 
 
 7:50 
 
 8:05 
 
 0.084 
 
 +2
 
 
 FATIGUE EFFECTS AND SUGAR CONTENT OF BLOOD 157 
 
 They conclude that normally the blood sugar varies Uttle when the 
 body is at rest and fasting, but that fatiguing work by healthy 
 adults generally causes a sUght decrease in the sugar content of 
 the blood. The values fluctuate and the lowest value is found at 
 varying intervals after the end of the work. The difference 
 between the rest value and this lowest value amounts on the 
 average to 0.020. There is then a gradual increase in blood 
 sugar, the maximum increase occurring from one and one half 
 to four hours after the end of the work. 
 
 We realize that our data are not conclusive either as to the 
 expected change in sugar content of blood for children after cer- 
 tain kinds of activities or as to the use of blood sugar determina- 
 tions as a criterion of fatigue. The value of such a method can 
 only be determined by more intensive studies. So few data are 
 available of repeated tests on children under specified conditions 
 that we beUeve our records are important as a basis for further 
 investigations. 
 
 PROCEDURE 
 
 In December, 1920, eleven subjects were selected as being sus- 
 ceptible to fatigue effects to a greater extent than other children 
 under observation. The selection was made jointly with Dr. 
 Edith Lincoln, whose physical examinations of these children 
 indicated relatively low resistance to fatigue. Our selection was 
 based upon decrease in output as measured by psycho-physical 
 tests in the laboratory and also upon apparent effort expended 
 to make the scores. Only eight subjects, four boys and four 
 girls, were available for the complete experiment with the deter- 
 minations of sugar content in the blood. 
 
 Two series of laboratory tests were devised, one of relatively 
 simple muscular tests, the other invohdng more complex mental 
 reactions. An attempt was made to establish a standard or refer- 
 ence measure of blood sugar content for each individual for the 
 time of day at which the tests were to be given. Two blood sugar 
 determinations were made with a three weeks interval. These 
 determinations were made by Dr. Liggett Lincoln. In making a 
 determination the procedure was to bring the child up to the 
 laboratory for obtaining a specimen of blood, after which he went
 
 158 BUFORD J. JOHNSON 
 
 back to the school room without any work in the psychological 
 laboratory on those days. This was also held to be desirable for 
 adapting the child to such conditions so that we might prevent 
 undue emotional excitation on the days of the test series. These 
 children are familiar with the laboratory and with the examiners; 
 both physician and psychologist have made studies of these 
 children throughout a period of two to three years in each case. 
 Although two children hesitated about the blood test, such ex- 
 periences as the punctures for blood specimens have not lessened 
 the interest of the children in coming to the laboratory, oppor- 
 tunities for which they solicit. This desire was the strongest 
 incentive during the experiment for one boy who has evinced fear 
 of even slight physical pain. Three weeks elapsed between the 
 time of the second preliminary blood test and the first experi- 
 mental series. The experiments were made at the same time of 
 day, between 9:30 and 12 in the morning, keeping the order of 
 individuals the same as far as was possible. Breakfast was not 
 omitted. Diet lists showing the food eaten at breakfast had been 
 obtained. The physician considered the breakfasts for all the 
 children fairly standardized as to amount and type of food. More 
 than two hours elapsed between breakfast and test in each case. 
 
 A preliminary study was made of the test used in order to 
 determine a series of simple muscular tests in which practice 
 effects could be practically eliminated, and to acquaint the child 
 with the procedure so that he would be at a high level of activity 
 between blood tests. In the spring preceding this study, the 
 target, coordination, tapping, and dynamometer tests were given 
 to a group of children including those to be used in the fatigue 
 experiments. Trials were given daily for nine school days, 
 Saturday and Sunday intervening between the fifth and sixth 
 trials. The curves in figures 1 and 2 show an approximate ehm- 
 ination of practice effects in tapping and coordination. The 
 target records for 30 throws a day continued to show marked 
 fluctuations with little trend toward increased skill in many 
 cases. It was a favorite performance; and the throwing of 
 100 darts in the fatigue experiment offered an activity adequate 
 to the production of muscular fatigue activity which mere scores 
 do not measure.
 
 TRIALS * 
 
 FiQ . 1 . Showing the Practice Effects in the Tapping Test, Alternate Plate 
 
 The light lines are individual curves; the heavy line is a group curve repre- 
 senting the daily average scores. 
 
 Fig. 2. Showing the Practice Effects in the Coordination Test 
 
 The light lines represent individual scores; the heavy line, average scores for 
 the group. 
 
 159
 
 n 
 
 160 BUFORD J. JOHNSON 
 
 Series I. Simple muscular tests 
 
 This series included: Target, 100 throws with right hand; 
 dynamometer, 10 trials, left hand; tapping, alternate plate, for 
 two minutes with right hand; tapping, single plate, for two 
 minutes with left hand. They were given in the order Usted. 
 The target test was that described by the writer (7) in a former 
 article. The dynamometer and single tapping tests were given 
 according to directions of Woolley and Fischer (8). The alter- 
 nate tapping plate (9) was so wired that Stoelting make and 
 break counters recorded separately the number of taps for each 
 plate. The child was instructed to strike first one plate and 
 then the other. A few taps were not recorded because the 
 dividing block was struck instead of the plate and also failure 
 to touch the plate was noted even when movement was made 
 approximating contact. 
 
 Immediately before the child came into the room for the test- 
 ing a specimen of blood was obtained by the physician in an 
 adjoining room. The testing required from twenty to twenty- 
 five minutes, varying shghtly for individuals because of time 
 variations possible in two tests, the dynamometer and target. 
 Another specimen of blood was obtained immediately after the 
 testing. 
 
 In table 1 the sugar content for the preliminary blood tests is 
 shown. We have not been able to get definite standards as to 
 normal sugar content of blood for the ages considered.^ Some 
 of these children vary between the first and second tests as much 
 as 11 mgm. per 100 cc. while others show as little variation as 
 1 mgm. per 100 cc. The average sugar content for the group for 
 the first blood test was 113.57; for the second test, 117; for the 
 third test, 120.125. Of the six individuals considered, two 
 
 2 Norms vary for different observers. Summaries of these normal values are 
 given by A. Mertz, Archiv. fur Kinderheilkunde, 1920, Ixviii, 260. From 2 to 5 
 years, blood sugar values range from 0.084 to 0.100; from 2 to 8 years, 0.080 to 
 .120; from2 to 14 years, .072 to .113; from 6 to 14 years, .072 toO .108. Mertz, 
 A. and Romiger, E., Archiv. fur Kinderheilkunde, 1921, Ixix, 105, give additional 
 data for ages from 7 days to 1 year, 7 days, for which the blood sugar values range 
 from .068 to .101 with average of .081 .
 
 FATIGUE EFFECTS AND SUGAR CONTENT OF BLOOD 
 
 161 
 
 cases show a decrease with variations relatively large. The 
 range of individual variations is from to 26. Only one case 
 shows a decrease in sugar content from the preceding blood test, 
 
 TABLE 1 
 Preliminary blood sugar tests 
 
 G. P., girl. 
 J. S., boy.. 
 
 D. P., girl. 
 T. F., boy. 
 E.G., boy. 
 
 E. R., girl. 
 J. M., boy. 
 M. D., girl. 
 
 Average. 
 
 AOB 
 
 AT FIRST 
 
 BLOOD 
 
 TEST 
 
 years 
 
 6.04 
 7.22 
 7.70 
 8.29 
 8.86 
 8.87 
 9.14 
 11.01 
 
 HEIGHT- 
 WEIGHT 
 INDEX 
 
 0.95 
 0.92 
 1.03 
 1.18 
 1.08 
 1.07 
 1.18 
 1.23 
 
 BLOOD SUGAR 
 (UGM. PER 100 OC.) 
 
 December January 
 18, 1920 8, 1921 
 
 0.090 
 0.139 
 0.105 
 
 0.128 
 0.112 
 0.110 
 0.111 
 
 113 .57 
 
 0.100 
 0.128 
 
 0.120 
 0.120 
 0.116 
 0.115 
 0.120 
 
 117 
 
 TABLE 2 
 Series I. Simple muscular exercise 
 
 
 TARGET 
 BCOBE 
 
 DTNAMO- 
 
 METER 
 
 AVERAGE 
 
 8CORK 
 
 TAPPING (2 MINtTTE PERIOD) 
 
 BLOOD BUGAR 
 (mom. PER 100 OC.) 
 
 
 Single plate 
 
 Alternate 
 plate 
 
 Before 
 exercise 
 
 After 
 exercise 
 
 G. P. 
 J. S. 
 D. P. 
 T.F. 
 E.G. 
 E.R. 
 J.M. 
 M.D. 
 
 65 
 
 246 
 82 
 222 
 117 
 140 
 342 
 169 
 
 9.3 
 8.2 
 11.0 
 14.1 
 11.6 
 7.7 
 12.6 
 12.3 
 
 526 
 429 
 517 
 286 
 591 
 429 
 510 
 411 
 
 344 
 268 
 424 
 258 
 446 
 361 
 423 
 510 
 
 0.120 
 0.130 
 0.102 
 0.126 
 0.120 
 0.090 
 0.128 
 0.145 
 
 0.126 
 0.125 
 0.110 
 0.152 
 0.124 
 0.120 
 0.130 
 0.142 
 
 Average 
 
 120.125 
 
 128 .63 
 
 
 
 but this is the largest variation found. Another case shows 
 an increase of 25. These two individuals seem especially sus- 
 ceptible to fatigue and are also easily stimulated to emotional 
 responses. These percentages of blood sugar are high as com-
 
 162 
 
 BUFORD J. JOHNSON 
 
 pared with values usually given for children and adults. They 
 exceed any blood sugar given by Brosamlen and Sterkel (10) for 
 healthy adults. When we average the three blood sugars preced- 
 ing series I for each individual and get the group average we 
 have 117.89 with standard deviation of 8.44. The group average 
 after the tests was 128.63 with a standard deviation of 12.142. 
 The difference between this and the average of the blood sugar 
 determinations preceding the testing is 8.5 which equals 1.78 
 times the probable error. Correlation of the blood sugar ratings 
 immediately before series I with those immediately after gives 
 r = 0.53. There is e^ddent a sUght increase in blood sugars after 
 the simple muscular exercise. 
 
 TABLE 3 
 
 Repetition of muscular tests, April 19, 1921 
 
 
 DTNAMOMETEE 
 AVERAGES 
 
 
 TAPPING — SEPARATE PLATES 
 
 BLOOD 8CQAR 
 (MGM. PER 
 
 
 FOB RIGHT HAND 
 
 ADDING 
 MA- 
 
 
 100 CC.) 
 
 
 Right hand 
 
 Left hand 
 
 
 
 
 
 
 
 
 
 :2| 
 
 T3.2 
 
 1" 
 
 
 CHINE 
 
 
 
 (3 
 
 S 
 
 
 (1) 
 
 (2) 
 
 (3) 
 
 (1) 
 
 (2) 
 
 (3) 
 
 < 
 
 T. F. 
 
 22.2 
 
 19.2 
 
 20.7 
 
 
 472 
 
 450 
 
 522 
 
 445 
 
 521 
 
 441 
 
 115 
 
 120 
 
 E. R. 
 
 13.2 
 
 13.4 
 
 12.8 
 
 56 
 
 * 
 
 477 
 
 378 
 
 * 
 
 354 
 
 275 
 
 112 
 
 125 
 
 M.D. 
 
 19.4 
 
 22.0 
 
 18.0 
 
 66 
 
 494 
 
 435 
 
 436 
 
 436 
 
 422 
 
 369 
 
 116 
 
 118 
 
 * Wire was loose and record lost for first trials. 
 
 Two of these children showed such a large amount of sugar and 
 one showed so great an increase in sugar content that a repeti- 
 tion of muscular tests was made. Blood sugar specimens were 
 again obtained immediately preceding and following the tests. 
 The tests given were tapping, dynamometer and exercise upon an 
 adding machine. The tapping was done with both hands on 
 separate plates with the board so wired that records were sepa- 
 rately kept for each hand. Three trials were given with thirty 
 second intervals. With the dynamometer fifteen trials were made 
 with the right hand. The adding machine was arranged so 
 that 1 was printed each time the handle was pushed back. The 
 child was instructed to do this as rapidly as possible. It was
 
 FATIGUE EFFECTS AND SUGAR CONTENT OF BLOOD 163 
 
 continued for one minute. The sum printed was recorded as the 
 score. 
 
 The sugar content for two of these cases was not nearly so high 
 before these activities as in the first series and there is but a 
 slight change after exercise. The third case has a sugar content 
 higher by 22 than that preceding the first muscular tests but does 
 not show so great an increase after exercise, though the blood 
 sugar then is the highest for this child during the experiment. 
 A slight increase in blood sugar after exercise is found for all 
 three subjects. 
 
 Series II 
 
 The second series for producing fatigue from more complex 
 reactions involving little muscular exercise was given May 17, 
 1921. The same procedure was followed in obtaining blood 
 specimens both before and after the activities in the laboratory. 
 The tests were given in the following order: coordination, 
 discrimination, memory for digits, and substitution. In the 
 coordination test (fig. 3) the child was instructed to trace a path 
 without touching the sides, but in tracing a given segment to 
 make a stroke of the pencil to the beat of the metronome. This 
 was set at one hundred beats per minute. An actual record 
 made during the experiment is shown in figure 3. Number 
 of contacts and time were recorded. 
 
 The discrimination test involved the sorting of fifty-two ordi- 
 nary playing cards. In the center of each card was cut a dia- 
 mond-shaped hole. The holes were so cut that in thirteen cards 
 the long axis of the diamond was lengthwise the card; in thirteen 
 cards it was crosswise the card; in thirteen cards it extended in 
 the diagonal from the upper right to the lower left; in the re- 
 maining cards from the upper left to the lower right. A wooden 
 receptacle of five open stalls was clamped to a table under an 
 adjustable screen so that the stalls and cards could not be seen. 
 The cards, carefully shuffled, were placed in the end stall at the 
 left. The subject was instructed to take from the top of the pack 
 one card at a time with the left hand and while holding it in this 
 hand to run the thumb and forefinger of the other hand around
 
 164 BUFOKD J. JOHNSON 
 
 Fig. 3. An Actual Record in the Coordination Test
 
 FATIGUE EFFECTS AND SUGAR CONTENT OF BLOOD 165 
 
 the edge of the hole. He was then to place the card in that stall 
 designated for cards with the diamond in that position. The 
 sorting continued in this manner until all the cards had been 
 distributed. The record sheet in figure 4 shows the type of errors 
 made. 
 
 G.P . 
 
 7- 17" 
 
 J. S. 
 
 11*20" 
 
 O.P. 7 7 
 
 tiO 0O 
 
 \:^9 4 5 11 
 
 \:\i 2 
 
 W() Po 
 
 0* '- 
 
 00 1 
 
 5 1 
 
 1 
 
 0' ^ 
 
 00 1 
 
 8 5 
 1 2 
 
 06122 
 
 {:J 1 9 
 
 O 
 
 1 1 
 
 OO 
 
 1 
 
 03 4 1 1 
 
 SCORE 
 
 22 
 
 
 27 
 
 29 
 
 t.F. 
 
 8* 35' 
 
 E. C. 
 
 14*32" 
 
 J. M. 6*10** 
 
 ^1 
 
 ' 
 
 
 0O 
 
 1 
 
 tiO 0O 
 
 \^]0 2 1 
 
 09 U 
 00 1 
 
 3 
 9 
 
 0' 12 
 
 0y 
 
 4 
 1 ) 
 
 Oo i 2 3 
 (^3 2 10 1 
 
 o° ° 
 
 13 
 
 OO 
 
 U 
 
 O i 
 
 SCORE 
 
 38 
 
 M.D. 
 
 39 
 
 6*55- 
 
 38 
 
 
 
 C^lJ 1 
 
 
 
 
 Ot 13 
 
 00 
 
 4 
 8 
 
 
 
 
 o° <» 
 
 13 
 
 
 
 
 SCORE 
 
 46 
 
 
 FiQ. 4. Record of Time and Placements in the Discrimination Test 
 
 In the test of memory for digits the procedure followed was 
 that described in the monograph by Woolley and Fischer" (11) 
 previously mentioned. The substitution blank used was a sym- 
 bol form devised by Dunlap. A record made by the youngest
 
 166 
 
 BUFORD J. JOHNSON 
 
 r.. 
 
 - L. O /N X ^ 
 
 1^ 
 
 
 
 
 
 
 
 A -1 
 
 
 
 
 
 u 
 
 1^ 
 
 r-r-} 
 
 ^ 
 
 
 
 
 
 =: X — 
 
 1^ ^ 
 
 /| (7 
 
 L 
 
 ;= L 
 
 
 
 X 
 
 
 
 -^ 
 
 ^ 
 
 
 
 L 
 
 L \ 
 
 I' ' I T 
 
 
 
 
 \ 
 
 A 
 
 A, 
 
 
 
 ^ ^ 
 
 % A '^ 
 
 ® 
 u X - 
 
 /( I 
 
 6 
 
 A 
 
 
 
 
 
 
 
 
 
 Fig. 5. Record Made by the Youngest Child in the Substitution Test
 
 FATIGUE EFFECTS AND SUGAR CONTENT OF BLOOD 
 
 167 
 
 child is shown in figure 5. It was required that sjinbols be 
 substituted for symbols. 
 
 TABLE 4 
 Series II, May 17, 1921 
 
 
 MOTOR COORDINATION 
 TEST 
 
 FORM DISCRIMINATION 
 
 MEMORY FOR 
 
 DIGITS 
 
 SUBSTITCTION 
 (FORM 1) 
 
 
 Time 
 
 Number of 
 contacts 
 
 Time 
 
 Score 
 
 Span 
 
 Score 
 
 Time 
 
 Errors 
 
 G.P. 
 
 1'26" 
 
 38 
 
 7' 17" 
 
 20 
 
 5 
 
 40 
 
 4' 16" 
 
 
 
 J. S. 
 
 I'll" 
 
 36 
 
 11' 20" 
 
 27 
 
 6 
 
 66 
 
 4' 10" 
 
 
 
 D. P. 
 
 I'SO" 
 
 20 
 
 7' 7" 
 
 29 
 
 7 
 
 100 
 
 3' 4" 
 
 1 
 
 T.F. 
 
 1'29" 
 
 42 
 
 8' 35" 
 
 38 
 
 4 
 
 31 
 
 2' 43" 
 
 
 
 E.G. 
 
 I'lO" 
 
 38 
 
 14' 32" 
 
 39 
 
 9 
 
 175 
 
 3' IS" 
 
 
 
 J.M. 
 
 1'20" 
 
 14 
 
 6' 10" 
 
 38 
 
 9 
 
 164 
 
 3' 4" 
 
 2 
 
 M.D. 
 
 1' 4" 
 
 26 
 
 6' 55" 
 
 46 
 
 7 
 
 101 
 
 2' 28" 
 
 
 
 TABLE 5 
 Series II. Blood sugar, blood pressure and urinalysis, May 17, 1921 
 
 
 BLOOD SUGAR 
 
 
 
 
 
 
 
 
 (mgm. per 
 100 cc.) 
 
 PRES8DBE 
 
 URINALYSIS 
 AFTER 
 
 PREVIOUS BLOOD PRESSURES 
 
 
 
 
 
 EXERCISE 
 FOB SUGAR 
 
 
 
 
 
 
 Before 
 exercise 
 
 After 
 exercise 
 
 Before 
 exercise 
 
 After 
 exercise 
 
 1918-19 
 
 1919-20 
 
 1920-21 
 
 G.P. 
 
 85 
 
 89 
 
 88 
 60 
 
 102 
 62 
 
 None 
 
 78 
 58 
 
 78 
 56 
 
 92 
 62 
 
 90 
 70 
 
 J.S. 
 
 90 
 
 88 
 
 108 
 
 74 
 
 90 
 
 68 
 
 None 
 
 
 
 90 
 
 58 
 
 94 
 
 72 
 
 D. P. 
 
 81 
 
 84 
 
 96 
 
 72 
 
 96 
 68 
 
 None 
 
 90 
 58 
 
 92 
 60 
 
 88 90 
 62 56 
 
 92 
 68 
 
 T.F. 
 
 88 
 
 90 
 
 102 
 
 72 
 
 98 
 76 
 
 None 
 
 106 
 66 
 
 110 
 66 
 
 96 
 
 58 
 
 104 
 76 
 
 E.G. 
 
 92 
 
 85 
 
 110 
 76 
 
 110 
 
 72 
 
 None 
 
 
 
 
 98 
 76 
 
 J.M. 
 
 100 
 
 102 
 
 96 
 64 
 
 100 
 66 
 
 None 
 
 78 
 66 
 
 82 
 66 
 
 90 90 
 64 64 
 
 98 
 76 
 
 M.D. 
 
 101 
 
 110 
 
 122 
 
 78 
 
 98 
 
 78 
 
 None 
 
 88 
 64 
 
 86 
 64 
 
 88 
 62 
 
 106 
 
 78
 
 168 BUFORD J. JOHNSON 
 
 In table 5 it is shown that the sugar content immediately 
 preceding these tests was lower in each case than in previous 
 determinations. The variation after exercise is less than that 
 between any other two measures except in two cases. 
 
 We have no explanation for the fall in sugar content unless it 
 is due to seasonal variation,' such as reported by Strouse (12). 
 The blood pressure and urinalysis add httle to the interpretations. 
 It might be argued that emotional excitation in preceding de- 
 terminations influenced the sugar content. That a child should 
 be so much affected in four or six blood tests and not in the next 
 can not be assumed. This fall is noted for the children who had 
 supplementary tests and for those who did not. The preceding 
 activities and breakfasts were approximately the same as in 
 preceding tests. 
 
 DISCUSSION AND SUMMARY 
 
 The range in chronological age is such as to invaUdate direct 
 comparisons of output and changes in sugar content. We give 
 the records to indicate the actual work done by each individual. 
 In the preliminary study of tests for use in this investigation we 
 found a decrease in tapping scores for the fourth period of thirty 
 seconds as compared with the first period. The graphs in figure 
 6 show this diminished output for each of the nine practice peri- 
 ods. While the decrease fluctuates from day to day, there is 
 no tendency towards a lessening of this difference with increas- 
 ing practice. Individuals vary as to the period in which least ca- 
 pacity is shown. If a higher level of efficiency is maintained for 
 the first two periods there often results a marked decrease in the 
 third period, with perhaps a slight increase for the fourth or 
 final period. Others show a gradual diminution in capacity 
 from the first to the final period. The fluctuations in the group 
 curves II, III, and IV are probably due to these individual 
 differences. 
 
 ' Strouse found that the average blood sugar readings were higher in the cooler 
 part of the year. Daily variations of blood sugar percentage occurred in five 
 normal persons. These variations seem to depend on changes in the weather.
 
 FATIGUE EFFECTS AND SUGAR CONTENT OF BLOOD 
 
 169 
 
 Fig . 6 . Showing the Daily Scores for Thirty-Second Periods in the Tapping 
 Test, Alternate Plate, for Nine Children 
 
 I, Average daily score for first period; II, for second period; III, for third 
 period; IV, for fourth period. 
 
 TABLE 6 
 Individual variations 
 
 
 FIRST AND 
 
 SECOND 
 
 PBELIMI- 
 
 NABT 
 
 SECOND 
 PRELIMI- 
 NARY AND 
 BEFORE 
 SERIES I 
 
 BEFOHB 
 
 AND AFTER 
 
 SERIES I 
 
 AFTER 
 SERIES I 
 
 AND 
 BEFORE 
 SERIES II 
 
 BEFORE 
 AND AFTER 
 8BBIES II 
 
 AVERAGE 
 DEVIATION 
 
 G. P 
 
 10 
 -11 
 
 -8 
 4 
 5 
 9 
 
 10 
 
 2 
 
 6 
 
 
 
 -26 
 
 13 
 
 25 
 
 6 
 -5 
 
 8 
 26 
 
 4 
 30 
 
 2 
 -3 
 
 -41 
 -35 
 -29 
 -64 
 -32 
 
 -30 
 -41 
 
 4 
 
 -2 
 3 
 2 
 
 -7 
 
 2 
 9 
 
 14 2 
 
 J.S 
 
 11 
 
 D. P 
 
 13 3 
 
 T.F 
 
 24 5 
 
 E.C 
 
 10 2 
 
 E.R 
 
 
 J. M 
 
 10.4 
 
 M.D 
 
 17 4 
 
 
 
 Average 
 
 7.83 
 
 11.71 
 
 10.5 
 
 38.85 
 
 4.14 
 
 14.43
 
 170 
 
 BUFORD J. JOHNSON 
 
 The individual variations shown in table 6 indicate little 
 stability in blood sugar for a given individual under the condi- 
 tions of the experiment. We find that a child may show a rela- 
 tively high sugar content before exercise and either slight or 
 marked increase after exercise. Relatively low content of sugar is 
 also found preceding exercise with a rise of as much as 0.030 after 
 exercise. In some cases a slight decrease is found. We do not 
 know whether such variations are due to a slow rise or to a slow 
 fall in sugar content; to the amount and kind of activity; or to 
 affective factors. Individual E. C, who has been characterized 
 as fearful of slight physical pain and with whom the physician 
 reasoned for some minutes before securing assent to the blood 
 test preceding series I, shows the least average variation. The 
 change in sugar content as shown by determinations made on the 
 same day preceding and after exercise is less on the average than 
 the total group variation. This group average is heavily weighted 
 by the variation in blood sugars obtained April 19, 1921, and 
 May 17, 1921. This we attribute to elevation of temperature. 
 The weather conditions on the days of the experiment were as 
 follows : 
 
 
 DECEM- 
 BER 18, 
 1920 
 
 JANU- 
 ARYS, 
 
 1921 
 
 JANU- 
 ARY 26, 
 1921 
 
 APRIL 19, 
 
 1921 
 
 MAY 17, 
 
 1921 
 
 Temperature at 9 a.m. F 
 
 Humidity at S a.m 
 
 29.0 
 0.66 
 29.71 
 
 39.0 
 0.96 
 29.72 
 
 12.0 
 
 0.52 
 30.45 
 
 39.0 
 0.90 
 29.92 
 
 48.0 
 0.65 
 
 Barometer at 8 a.m 
 
 30.22 
 
 
 
 The effects of this seasonal change in sugar content as related to 
 the optimal schedule of activities for school children merits in- 
 vestigation. If we exclude this factor, the change in sugar 
 content for series I, simple muscular exercise, appears more 
 significant. Two children stand out from the group with regard 
 to the internal conditions under which work is performed. 
 In the preUminary practice series for tapping test, alternate plate, 
 the relative capacity of these two children is shown by the follow- 
 ing results.
 
 FATIGUE EFFECTS AND SUGAR CONTENT OF BLOOD 
 
 171 
 
 Average total output 
 
 Average daily output 
 
 Average for 1st 30 outputs. 
 Average for 4th 30 outputs. 
 
 GROtP 
 
 E. R. 
 
 3769 .33 
 418.80 
 113.79 
 100 .78 
 
 3377.00 
 
 375 .00 
 
 99.44 
 
 92.55 
 
 2552 .00 
 
 364 .00 
 
 98.00 
 
 92.71 
 
 It is evident that the stimulating effects of environmental factors 
 are widely different for different children. 
 
 Conclusions as to the influence of different kinds and amounts 
 of activities upon the sugar content of the blood would be un- 
 warranted by our data. We believe that they indicate a method 
 of investigation that may clarify the concepts of fatigue and lead 
 to a reformulation of the factors involved in fatigue effects. 
 It seems essential that we make successive determinations 
 throughout a stated period of the day and over a period of time 
 sufficiently long for us to know what the normal changes are for 
 the individuals under observation. Determinations should be 
 made at short intervals preceding and following specific activities 
 which vary in complexity and in motivation. 
 
 REFERENCES 
 
 (1) Schneider, E. C, and Havens, L. C. : Changes in the blood after muscular 
 
 activity and during training. Amer. Jour. Physiol., 1915, xxxvi, 256. 
 
 (2) Cannon, W. B.: Bodily changes in pain, hunger, fear and rage, 211. 
 
 (3) Stewart, G. N., and Rogoff, J. M.: Further observationte of relation 
 
 of adrenals to certain experimental hyperglycemias. Amer. Jour. 
 Physiol., 1920, Ivii, 376. 
 
 (4) Bainbridge, F. a.: The physiology of muscular exercise, 128-138. 
 
 (5) Scott, E. L., and Hastings, A. B. : A study of the sugar and oxygen relation- 
 
 ships in the blood of dogs during exercise. Proc. Soc. Exper. Biol, 
 and Med., 1920, xvii, 120-122. 
 
 (6) Brosamlen, O., and Sterkel, H.: Der Einfluss von Muskelarbeit auf den 
 
 Blutzuckergehalt. Deutsches Arch, fur Klin. Med., 1919, cxxx, 360- 
 363, 371-372. 
 
 (7) Johnson, B.: Practice effects in a target test — a comparative study of 
 
 groups varying in intelligence. Psychol. Rev., 1919, xxvi, 300-316. 
 
 (8) WooLLEY, H. T., and Fischer, C. R.: Mental and physical measurements 
 
 of working children, 52, 75. 
 
 (9) DuNLAP, K.: Improved form of steadiness tester and tapping plate. Jour. 
 
 of Exper. Psychol. 1921, vol. IV, 430-432. 
 (10) Brosamlen, O., and Sterkel, H.: 0-p. cit., p. 360-363. 
 'XI) WoOLLEY, H. T., AND FiSCHER, C. R.: Op. cit., p. 123. 
 U -) Strotjse, S.: Some variations in normal blood sugar. Archiv. Int. Med., 
 
 1920, xxvi, 758. 
 
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