The beginning of a new year can wipe the slate clean for new life and work goals. But if your vacation was hectic, you might not be starting from scratch when it comes to your sleep. Missing even small bits of sleep for a few nights can turn into a sleep debt that could carry you into 2026. While you probably won’t be able to get enough sleep to eliminate that deficit, you can take steps to support the parts of your body that bear the biggest load.
Some of the consequences of owing your body to sleep are readily apparent, such as feeling sleepy, irritable, or fuzzy-brained, or contracting seemingly every virus. But other effects may be less noticeable. For example, the impact on your cardiovascular system, which increases over time. “Lack of sleep increases inflammation and stress hormones, which puts additional pressure on the heart and blood vessels, increasing the risk of high blood pressure and heart disease,” Angela Holliday-Bell, MD, board-certified physician and sleep specialist, tells us.
Added to these damages are the metabolic consequences. Skimping on sleep (even just for a night or two) can decrease your sensitivity to insulin, the hormone that tells your cells to absorb sugar from your blood, raising your blood glucose levels. That increases the risk of type 2 diabetes, amplifies heart attack, and also impairs the brain’s ability to create energy from glucose, tells us Louisa Nicola, MMed, a New York-based neurophysiologist who studies Alzheimer’s disease in women. Over time, that can make your brain less resistant to stressors like illness and aging, accelerating changes related to dementia.
Getting out of sleep debt can be more complicated than it seems
Just like racking up credit card debt, the larger your sleep deficit, the harder it will be to pay it off and get back to your baseline. Consider a scenario where you sleep one hour less than you need each night during the week. Which means that come the weekend, you’d have to sleep five more hours to make up the shortfall. “The problem is that our ability to sleep is not determined just by our desire to sleep or by the level of tiredness one feels based on how long one has been awake,” says Jennifer Martin, PhD, spokesperson for the American Academy of Sleep Medicine and professor at the Herbert Wertheim College of Medicine at Florida International University. “It is also governed by our circadian rhythm, which will not only allow us to sleep five hours later than normal to offset that debt.”
Even trying to catch up on more than a couple hours of sleep over the course of a weekend is a challenge when your internal clock wants you to wake up at your usual time, Dr. Martin adds. And if you manage to get a little more sleep on your days off, it still “won’t completely erase the impact of days of insufficient sleep on the body,” Dr. Holliday-Bell says. As with monetary debt, avoiding dormant debt in the first place will always be easier than paying it off.
If you have some sleep debt, a burst of high-intensity exercise can help you recover.
Sometimes losing sleep for a few days or more is almost inevitable, for example due to a rough patch at work or the reality of life as a new parent. Or maybe you’re struggling with insomnia and, despite your best efforts, you’re falling short. You probably know how to temporarily put yourself on alert: cold water on your face, a walk outside, an extra-caffeinated drink. But research suggests that you may also want to do a small dose of high-intensity exercise. It could go beyond combating drowsiness, also helping to partially compensate for some of the repercussions of lack of sleep on the body.
