For about six months I got a headache every Saturday morning around 10 AM. I assumed it was stress — the crash after a hard week. Made sense emotionally. Made zero sense biologically. Stress headaches usually happen during stress, not the morning after it ends.

My doctor asked two questions that cracked the case: “What time do you wake up on Saturdays?” and “When do you have your first coffee?”

It Is Probably Caffeine Withdrawal

Weekend headaches are most commonly caffeine withdrawal. If you drink coffee at 7 AM on weekdays but sleep until 9 on Saturday, your body expects caffeine at the same time. When it does not get it, blood vessels in your brain dilate — that is the headache. It is a real physiological response, not in your head. Well, it is in your head. But not the way you meant.

The fix: wake up at roughly the same time every day, or at least have your caffeine at roughly the same time. Even just drinking a small cup at your normal time and then going back to sleep prevents the withdrawal headache.

Other Weekend Headache Causes

Caffeine is the main culprit but it is not the only one:

• Sleep pattern change. Sleeping significantly later on weekends changes your circadian rhythm. Your body releases cortisol at your normal wake time whether you are awake or not. When you are still asleep during that cortisol spike, it can trigger a headache.
• Dehydration. Weekday routines include regular water breaks. Weekend routines — errands, yard work, Netflix — often do not. You get to 2 PM and realize you have had nothing but coffee since breakfast.
• Missing meals. Skipping breakfast because you slept late drops your blood sugar. Low blood sugar triggers headaches in some people.
• Screen position. Weekend lounging often means looking down at a phone or laptop from a couch for hours. That forward head position strains neck muscles that refer pain to your head.

The Simple Fix

Keep your sleep and wake times within one hour of your weekday schedule. Have caffeine within an hour of your normal time. Drink water before you feel thirsty. Eat breakfast within an hour of waking up. Four small habits that prevent a whole day of pain.