These sleep habits may put your heart at risk

Researchers tracked participants’ sleep patterns for close to a decade using wearable devices. The regularity of bedtime, wake-up time, and the midpoint between falling asleep and waking could predict heart trouble years later. People averaging less than eight hours of sleep were particularly vulnerable.

In this group, irregular bedtimes and variable mid-sleep times were a “significant risk factor” for major cardiac events. By contrast, getting more than eight hours of sleep a night appeared to buffer against heart issues regardless of bedtime or sleep midpoint, the study found.

Lead author Laura Nauha said the results suggest that the regularity of bedtime, in particular, may be important for heart health because it reflects the rhythms of everyday life and how much they fluctuate, according to Science Alert.

The researchers proposed that uneven bedtimes may disrupt the body’s circadian clock, potentially limiting optimal overnight recovery for the heart. They also noted that wake-up time did not appear to have much impact in their analysis.

In a separate study, an Australian-led team reported a 30 percent greater likelihood of heart attack, stroke, or heart failure when sleep apnea severity fluctuates dramatically across consecutive nights. The findings were published in the journal SLEEP.

The team analyzed home-based recordings using under-mattress sensors. They concluded that not only overall obstructive sleep apnea severity matters, but also instability from one night to the next, a pattern that could impose “repeated up and down strain” on the heart.

Severe apnea, higher night-to-night variability, and habitual snoring were linked to faster vascular aging, described as an early warning sign for cardiovascular disease.

The findings arrive amid growing recognition that circadian rhythm—the body’s 24-hour cycle governing hormones, metabolism, and other vital processes—may have wide-ranging implications for cardiovascular protection.