Waking up at 6:30 a.m. on weekdays and sleeping until noon on weekends may feel like catching up on rest. To your body clock, though, it can feel like crossing time zones every week.
A 2025 study published in the Journal of Epidemiology and Community Health examined seven days of sleep patterns in 72,269 adults and followed them for eight years. Compared with people who kept regular sleep schedules, those with the most irregular sleep had a 26% higher risk of major cardiovascular events, including heart attack, stroke, heart failure, and cardiovascular death.
Even more striking, getting enough hours of sleep did not fully erase the higher risk among those with the most irregular schedules. We often focus on sleeping for eight hours, but when we sleep matters, too.
A practical first step is to keep your wake-up time within roughly the same one-hour window each day. Get some morning light after waking to help set your body clock, then adjust your bedtime according to when you feel sleepy. If you work shifts, plan your exposure to light, sleep, and meals around your schedule.
If you still feel excessively sleepy after eight hours of sleep—especially if you snore, wake with a headache, or wake frequently during the night—it may be time to look more closely at your sleep quality and breathing.
Remember: sleep is not a bank account. Two extra hours on the weekend cannot simply cancel out a week of jet lag.
