POST-EXERCISE HEART RATE

and others with abnormal hearts, the post-exercise pulse of eleven
normal and eight abnormal cases is recorded.

The chi-square test is applied to the data to test the hypothesis
that there is no relationship between normality and abnormality of
the heart and the factor of secondary rise of pulse rate. Chi-square
was found to be .12. Since this value would be found by chance ap-
proximately 70 per cent of time, it is impossible to reject the hy-
pothesis that there is no relationship.

THE PULSE-RATIO

The Effect of the Resting Pulse Rate on the Pulse-Ratio.—In
order to observe the effect of the resting pulse rate on the pulse-ratio,
the significance of a difference in means of 29 subjects with resting
rates of 58 or less beats per minute and 34 subjects with resting
rates of 86 or more beats per minute is estimated by means of the
t-test.

The mean pulse-ratio of the low resting pulse rate sample is
2.909, and of the high is 2.757. The value of ¢ is 2.204. Ina large
number of samples like this, the value of t as large as 2.204 would
be found only between 5 per cent and 2 per cent of the time.

With such a high value of t, the hypothesis that the samples were
drawn at random from the same population may be rejected and it
may be said with a high degree of confidence that the means do
differ. Low resting rates are associated with high pulse-ratios and
high resting rates with low pulse-ratios.

The Relationship of the Rate of Stool-Stepping Exercise to the
Pulse-Ratio.—The linear proportionality between the pulse-ratio and
the rate of the exercise reported by Tuttle and others *5 does not
extend to light exercise. In fact, a stool-stepping exercise of ten
steps per minute may produce a higher pulse-ratio than a similar
exercise of twenty steps. An observation of the pulse-ratios of five
normal subjects tabulated below bears out this relationship.

 

 

 

Subject Pulse-Ratio Pulse-Ratio Pulse-Ratio Pulse-Ratio
Number at 10 Steps at 20 Steps at 30 Steps at 40 Steps
115 2.19 2.13 252 3.29
116 2.10 2.09 2.51 3.16
117 2.01 1.97 2.44 3.09
118 2.01 1.97 2.31 2.65

119 2.01 1.99 2.19 2.52

THE RECOVERY TIME

The Relationship of the Intensity of W eight-Lifting Exercises to
the Recovery Time.—The average recovery times of ten normal male

4W. W. Tuttle, “Response of the Heart to Exercise of Graded Intensity,”
Proc. Soc. Exper. Biol. and Med., 29 (March 1931) 598.

5W. W. Tuttle and G. Wells, “The Response of the Normal Heart to Ex-
ercises of Graded Intensity,” Arbeitsphysiol., 4 (Feb. 1931) 519.