Sleep Is The Original Anabolic — And Most Men Are Robbing Themselves

If you optimize one variable this year, make it sleep. Not training split, not creatine timing, not your morning routine. The thing that runs while you do nothing.

§What one bad week costs you

A 2011 JAMA study put healthy young men on five hours of sleep for one week. Their daytime testosterone dropped by 10 to 15 percent — the equivalent of aging them by a decade. One week.

Most men reading this haven't slept eight uninterrupted hours in a month.

§The four inputs that actually move the needle

Forget the 30-item sleep hygiene lists. Four things, in order of impact:

1. Temperature. Your bedroom needs to be between 60 and 67°F (16-19°C). Body temperature has to drop to trigger deep sleep. If you sweat, you don't sleep deep.
2. Light, both kinds. Bright light in your eyes within 30 minutes of waking. Near-darkness for the hour before bed. Your circadian system is run by the eyes, not the clock on the wall.
3. Caffeine cutoff at 2 p.m. Half-life of 5-6 hours means your evening coffee is still 25% active at midnight. You'll fall asleep — you just won't sleep deeply.
4. A consistent wake time, including Saturday. Sleeping in on weekends jet-lags you back into Monday morning. Your wake time is the anchor; bedtime drifts to meet it.

§What "good sleep" actually looks like on a tracker

I don't think you need a wearable to sleep well. But if you have one, these are the numbers worth watching:

• 7.5 to 9 hours in bed
• Resting heart rate within 3-4 bpm of your baseline
• HRV trending sideways or up over a 30-day average
• At least 90 minutes of deep sleep across the night

If your HRV craters two days in a row, you're not training through it. You're digging a hole.

§The supplement question

Magnesium glycinate before bed (around 300-400 mg) is the one I'd actually defend with evidence. Glycine itself, 3g, has small but real data behind it. Everything else — melatonin gummies, "sleep stacks," the rest — is either dosed wrong or doing nothing.

Get the four inputs right first. The supplement decisions get easier from there.