Alcohol Doesn't Just Cost You Tonight's Sleep — It Costs You Training Days
A night of drinking can suppress HRV, spike resting heart rate, and drain Body Battery — and if you're mid training block, that recovery hit can cost you more than just tomorrow.
Day 113: What Alcohol Actually Costs a Training Block
If you're training for something and you drink, the cost isn't just feeling rough the next morning. It shows up directly in the numbers your Garmin is already tracking — and it can take longer than a day to clear.
The mechanism, briefly
Alcohol shifts your autonomic nervous system away from recovery mode during sleep. That typically means a lower overnight HRV (heart-rate variability — the tiny variation in time between heartbeats, and one of your best recovery signals), a higher overnight resting heart rate, and a lower Body Battery recharge. For the full explanation of what HRV measures and how Garmin tracks it, see Day 92.
Why this matters mid training block
A single off night is not a big deal in isolation. The problem is stacking it on top of an already demanding week. If you're already carrying training load, a night of drinking pushes your recovery further into deficit right when your body needed the opposite. Concretely, that can show up as:
- A lower Training Readiness score the next day or two, not just the morning after
- A dip in HRV Status that takes more than one good night to fully recover
- Reduced quality in your next hard session — worse pace at the same effort, or a session that just feels heavier than it should
So it's not "one bad night." It's a multi-day dent in the exact system you're trying to build up.
What to do about it
You don't need to eliminate alcohol to train seriously — but timing matters. If you know a hard session or long run is coming up, keep the night before (and ideally two nights before) clean. Watch your own data: if HRV is below your normal range and resting heart rate is elevated, treat that as a real signal to dial back intensity, not just noise to push through.
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