[Finger temperature changes during exercise as related to exercise intensity].

Abstract

An approach was made to assess individual exercise tolerance using finger vasoconstrictive response as a marker for exercise intensity. Finger temperature (FIT) monitoring was used as an averaged flow sensor and was validated by finger plethysmography and laser-Doppler flowmetry. Progressive multi-stage intermittent exercise protocol (3-minute exercise period alternating with 3-minute rest period) was used to permit stable FIT values before each exercise stage. Anaerobic threshold (AT) was determined by respiratory measurements. Mean room temperature was 25.4 +/- 1.6 degrees C. The general pattern of FIT during 3-minute exercise period was as follows: at the mild exercise stage FIT decreased initially, only to rise at the latter half of exercise. As the exercise stage progressed FIT decreased throughout, and at the stage of maximal effort FIT decrease linearly (LiD). FIT decrease was abolished by the nerve block. Four groups of subjects (48 in total) were studied using the above-described exercise protocol. Group I; 6 athletes, II; 16 normal subjects, III; 8 mild cardiac and IV: 15 moderate to severe cardiac patients. Mean maximal oxygen consumption (ml/kg/min) was 70, 47, 31 and 15, and mean HR (b/min) was 188, 195, 165 and 142, respectively in group I, II, III, IV. LiD was observed in greater than 80% of all cases at the work load above 90% of peak oxygen consumption, and approximately 1.6-fold of AT in group I, II and III and 1.3-fold of AT in group IV. Correlation between plasma norepinephrine and FIT decrease was observed in normal subjects. In conclusion, FIT monitoring during treadmill exercise using intermittent protocol uncovered a work load dependent progressive vasoconstrictive response. And a linear decrease of FIT indicated an approaching maximal work load for the individual subject.