Acute partial sleep deprivation (PSD) has been shown to influence various physiological responses during exercise. This study, published in the American Journal of Physiology, Heart and Circulatory Physiology, aimed to explore the effects of acute PSD on cardiac output (Q̇) during moderate-intensity cycling in young adults.
The research involved 25 participants, averaging 22 years of age, who underwent a randomized, crossover trial. Each participant experienced two conditions: one where they slept normally and another where they had acute PSD, defined as early awakening that resulted in 40% of their normal sleep duration.
Throughout the study, blood pressure (BP), cardiac output, and cerebral artery blood velocity were measured at rest, during 60 minutes of moderate-intensity cycling, and during recovery. The results indicated that while systolic and diastolic BP did not differ significantly between the two conditions, cardiac output was notably affected.
At rest, cardiac output remained similar between the control (normal sleep) and PSD conditions (5.0 ± 0.9 L/min vs. 4.9 ± 0.7 L/min, P > 0.99). However, during the cycling exercise, cardiac output was significantly attenuated at the 60-minute mark (control: 12.3 ± 3.1 L/min vs. PSD: 11.5 ± 2.6 L/min, P = 0.003) and during recovery (control: 7.7 ± 1.9 L/min vs. PSD: 7.2 ± 1.4 L/min, P = 0.04).
Interestingly, while heart rate and estimated end-diastolic volume did not show significant differences (P ≥ 0.82), stroke volume tended to be lower following PSD (P = 0.07). Additionally, estimated ejection fraction was found to be lower (P = 0.02), and total peripheral resistance increased (P = 0.04) after PSD.
Furthermore, plasma norepinephrine and epinephrine levels did not change significantly at rest but showed attenuated increases during the 60 minutes of cycling following PSD (both, P ≤ 0.045). This suggests that the blunted cardiac output response observed after 30 minutes of cycling may be due to a reduced stroke volume, without a compensatory increase in heart rate.
In conclusion, the study highlights that acute partial sleep deprivation can lead to a significant reduction in cardiac output during moderate-intensity cycling, primarily due to changes in stroke volume and catecholamine responses.
What this study does not show
This study does not establish a direct causal relationship between acute partial sleep deprivation and long-term cardiovascular health outcomes.
Evidence scorecard
- Analytic validity: established
- Clinical validity: established
- Clinical utility: not established