I'm a parent of children under five, which means sleep deprivation isn't every now and then. It's just Tuesday, Wednesday, Thursday, if I'm lucky.

And while I know sleep matters for longevity, cortisol, stress, and general health, I also know that knowing that doesn't help me when I'm running on a few hours strung together.

So my question this week was a practical one: are there things we can do regularly to counteract the negative health impacts of sleep deprivation?

I sincerely hope there are, because otherwise I'm in trouble, and probably most other parents are too.

When researchers tested young women after a single night of sleep deprivation, their working memory was measurable impaired.

When they were asked to rate their performance, they thought they were performing as they normally would. That means, they were impaired, while thinking that they were fine.

A lot of the advice for sleep deprivation is aimed at making you feel more alert. They don’t necessarily restore thinking clearly: caffeine, in particular, rescues vigilance and reaction time, but only partially rescues complex reasoning, planning, and multi-step decision-making.

We need to acknowledge that our brain and its thoughts are likely less reliable with less sleep. That’s not really a surprise.

But here are a few things arising in the science that did surprise me.

Women’s vulnerability to sleep loss tracks our menstrual cycle. In a controlled study, women in the first half of their cycle (about two weeks from the day your period starts) had dramatic drops in performance compared to women in the second half (or men). Women in the second half of their cycle performed about the same as men.

If you’ve noticed that some bad nights feel survivable and some feel catastrophic, that may actually be the case. The same four hours of sleep is genuinely a different physical hit depending on where you are in your cycle.

It might be worth building more guardrails (to the extent possible) during that first half.

Light is one of the strongest signals your body uses to set its internal clock. Women’s bodies turn out to be unusually sensitive to it. Our circadian systems show a stronger response to brightness levels that don’t move men’s biology much at all.

And brightness matters in both directions — in the morning and at night.

To get the wake-up-and-reset effect on your brain that we want to counteract acute sleep deprivation, we need at least 2,000 lux. Indoor lighting is typically 100-500 lux. Even an overcast sky outside gets you 10,000 lux.

And you actually need to be outside to experience it properly. This is the root of the advice to get outside as early as you can in the morning.

At night, that sensitivity can work against us. Even dim bedroom light can shift our body clocks and delay natural sleepiness.

A controlled experiment testing nap lengths between 5 and 30 minutes suggests that the fastest way to feel alert again can be 10-30 minutes in the early afternoon.

Naps did not change hunger hormones, stress hormones, or appetites, however. Bad sleep makes your body less responsive to insulin (the hormone that controls blood sugar) and naps don’t fix that.

Exercise, on the other hand, during periods of bad sleep improved blood sugar control alongside other metabolic markers. If you’ve been sleeping badly for weeks and you’re worried about the long-term health costs, the answer is probably a walk after lunch, not a longer afternoon nap.

So, for those of you insisting on a workout (or have physically demanding work) despite a bad night, it’s worth keeping in mind that a 90-minute afternoon nap beat a 20-minute nap for physical performance and reduced muscle damage markers.

🧠 Pick one decision-protection rule before you need it. Examples: no work emails sent before 10 AM after a bad night. No financial decisions until you've slept normally for two nights. Whatever the rule, decide it now. Your sleep-deprived self isn't equipped to set it in the moment.

🩸 Track which half of your cycle you're in alongside your sleep. Most cycle-tracking apps already do this. Knowing you're in week one and running on four hours is the kind of context that lets you cancel the meeting you were on the fence about.

☀️ Keep cloudy-day clothes by the door. The biggest reason people skip morning light is weather. Putting out the right clothes can be the first step towards habit.

🌑 Buy a 2-watt warm bulb for your nightstand lamp. Most nightstand lamps run 40-60 watts, far above the threshold where evening light starts shifting your body clock.

🚶 Stack the post-meal walk with something you already do. Calling a parent, listening to a podcast, planning a meeting.