Effects of curtailed sleep on cardiac stress biomarkers following high-intensity exercise

Abstract

Objective: Physical exercise-especially at high intensity-is known to impose cardiac stress, as mirrored by, e.g., increased blood levels of cardiac stress biomarkers such as cardiac Troponin T (cTnT) and NT-proBNP. We examined healthy young participants to determine whether a few nights of short sleep duration alter the effects of acute exercise on these blood biomarkers.

Methods: Sixteen men participated in a randomized order in a crossover design, comprising three consecutive nights of a) normal sleep duration (NS, 8.5 h of sleep/night) and b) sleep restriction (SR, 4.25 h of sleep/night). Blood was repeatedly sampled for determination of NT-proBNP and cTnT serum levels before and after a high-intensity exercise protocol (i.e., 75% VO₂^maxReserve cycling on an ergometer).

Results: Under pre-exercise sedentary conditions, blood levels of cTnT and NT-proBNP did not significantly differ between the sleep conditions (P > 0.10). However, in response to exercise, the surge of circulating cTnT was significantly greater following SR than NS (+37-38% at 120-240 min post-exercise, P ≤ 0.05). While blood levels of NT-proBNP rose significantly in response to exercise, they did not differ between the sleep conditions.

Conclusion: Recurrent sleep restriction may increase the cardiac stress response to acute high-intensity exercise in healthy young individuals. However, our findings must be further confirmed in women, older subjects and in patients with a history of heart disease.

Keywords: Cardiomyocyte; Cardiovascular strain; Heart muscle; High-intensity exercise; Sleep loss; Troponin.