🧐 What’s sleep debt? Here’s how to check if you have any

I’ve been looking back on my sleep

When you don’t sleep as much as you need to, you start to accumulate sleep debt. Sleep debt builds up over time, so by sleeping less than usual for multiple nights in a row your sleep debt can progressively get worse and worse.

For most of us, this often manifests in the habit of what some experts call “yo-yo sleeping” - chronically under-sleeping during the week and oversleeping on the weekends. This is thought to be the body’s way of recovering from chronic short sleep and is probably a hint that you need to prioritise getting sufficient sleep every day of the week!

🔱 Sleep debt has multiple routes of attack on your health

A US Government’s CDC Morbidity and Mortality Report found that more than a third of adults regularly accrue a significant sleep debt. Given the data was based on self-reported stats, I wouldn’t be surprised if the actual statistics are worse!

The effects? If you are regularly getting less sleep than you need, you feel grumpier, have less concentration and your memory is impaired. Long term sleep deprivation has a number of health consequences such as obesity, diabetes, high blood pressure, heart attack, stroke and Alzheimer’s.

Insufficient sleep is linked to increased food intake, snacking, and worsened dietary choices and regularity of meal timings. It’s thought that this could have to do sleep restriction throwing off the endocrine system (especially the hormones ghrelin and leptin, which are responsible for appetite). But to make matters worse, sleep debt also affects glucose tolerance, decreases insulin sensitivity and increases levels of cortisol (the stress hormone) - all of which affect the metabolism and prompt the building of energy stores in the form of excess body fat.

💳️ The right strategy for when sleep debt starts piling up

So, can sleeping in on weekends, going to bed earlier the following night, or taking naps actually make up for your accumulated sleep debt? Yes and no.

This 2019 paper found that it may not be possible to undo some of the damage caused by prior sleep deprivation:

For example, it was seen that weekend catch-up sleep can’t reverse the metabolic dysregulation that can come with sleep loss.

Animal studies have found that even after a full year of regular sleep, mice that had previously been sleep-deprived still suffered from neural damages and brain inflammation. With multiple studies showing similar results, it’s now thought that much of the same can be said for humans: it’s not truly possible to fully recover from sleep deprivation.

So what can you do when things do, inevitably go wrong? By monitoring levels of the hormone melatonin, the scientists also found that combining sleep debt with weekend lie-ins shifted participants’ internal body clocks further out of whack than if they had just resumed a consistent sleep pattern.

🔍️ Actionable insight: avoid weekend lie-ins

While weekend lie-ins can be beneficial when needed most, the best and only long-term fix is to resume a consistent sleep schedule ASAP. You just can’t beat the corrective power of consistent bedtimes!

🛠️ My current Sleepstack:

• Screen filter software: Tools like f.lux (desktop), Twilight (Android) and Night Shift (iOS) change the colour of your display to based on the time of day to reduce overstimulating wavelengths.

• Sleep mask: Light affects melatonin secretion even when your eyes are shut. I find that a good sleep mask is a game-changer when it comes to deeper sleep (and a great alternative to blackout curtains). I use this one at the moment - I don’t think I can go back to life without it.