Sleep Duration Irregularity is Associated with Elevated Blood Pressure During Submaximal Exercise in Young Adults.

PURPOSE

Irregularity in nightly sleep duration is reported to associate with elevated blood pressure (BP), but it is unclear whether this association can be observed with BP measured during exercise after controlling for factors known to influence the exercise pressor reflex.

METHODS

Twenty-nine young adults (22±4y; 19 men, 10 women) performed cycling exercise until volitional fatigue to assess peak oxygen uptake (VO). Actigraphy was used to monitor sleep duration and daily physical activity for seven consecutive days after which participants completed two bouts of moderate-intensity cycling while BP and VO were measured using a Tango+ device and indirect calorimetry, respectively. Systolic BP was averaged from the two bouts of exercise and expressed as a change from seated rest (∆SBP). Sleep duration regularity was calculated as standard deviation (SD) and coefficient of variation (CV).

RESULTS

Systolic BP at seated rest, during exercise, and ∆SBP was 113±13, 152±21, and 38±13 mmHg, respectively. Sleep duration SD (range 10-146 min) and sleep duration CV (range 2-54%) when excluding weekend nights were significantly correlated with ∆SBP (r = 0.58 and r = 0.62, respectively; both <0.01) after adjusting for age, sex, body mass index, peak VO, physical activity, resting systolic BP, chronotype, and the VO response to exercise. Sleep duration regularity analyzed with weekend nights included (across all seven days) was also significantly correlated with ∆SBP (≤0.01), but had weaker correlation coefficients.

CONCLUSION

These results indicate that sleep regularity, especially when excluding weekend nights, is associated with the rise in systolic BP during moderate-intensity exercise in young adults. Sleep duration regularity may be a useful tool to capture the impact of intermittent nights of insufficient sleep on BP dysregulation.