Chronic stress and performance

You train well, eat well, rest on the days marked — and PRs don't come. If that sounds familiar, maybe it's not the plan. Maybe it's your nervous system asking for air.

Cortisol doesn't tell the difference between a hard boss and a 1000m rep

Your body has a single adaptation tank. When you train, that tank drains and refills with rest. When you live stressed — intense work, family issues, broken sleep, too much caffeine — the tank drains too. And it doesn't distinguish. To the endocrine system, an argument with your boss burns resources the same as a fartlek set.

Chronically elevated cortisol does three things that kill progression:

1. Blocks post-training recovery — muscle protein synthesis drops, glycogen takes longer to refill.

2. Hurts deep sleep — right when your body releases GH (growth hormone) and consolidates adaptations.

3. Raises submaximal heart rate — you go slower at the same effort. You read it as "I'm not fit" but it's stress.

Early signs you're missing

Before clinical overtraining (rare), there's fatigue accumulated from life stress. Signs:

Resting HR +5 bpm above your baseline for >5 days.

Low HRV relative to your 30-day average (if you have a monitor).

Sleep <6.5h or fragmented sleep (waking at 4 AM for no reason).

Flat mood: what used to hook you now feels like effort.

Weird thirst, weird sweating, night sweats.

Recurring colds ("I catch everything").

If three or more boxes tick — drop volume 30-40% for 7-10 days. Not resting is losing more time later.

What to do (concrete, not "meditate")

### Sleep as priority one

Eight hours, non-negotiable. If you sleep less than 7, drop the plan, not the bed. A week of 6h of sleep wastes a month of adaptation. The evidence is brutal: Mah et al (2011) showed that basketball players sleeping 10h/night improved free throws 9% and sprint times 5% — without touching training.

### Z2 helps, quality doesn't

If you're in a stressed life season (moving, divorce, new boss role, just became a parent), swap your Z4-Z5 sessions for extended Z2. Maintains aerobic base without charging a cortisol toll. It's counterintuitive: when you're more burned out, less intensity, not more volume.

### No caffeine after 2 PM

Caffeine half-life: 5-6 hours. You drink a mate at 4 PM, at 1 AM you still have 1/4 dose circulating. Blocks deep sleep. If you're stressed and want to sleep well, cut caffeine before 2 PM.

### Slow walking as medicine

Twenty minutes of conversational-pace walking, ideally with greenery around, lowers cortisol better than sitting down to "relax". It's not training — it's regulation. Add it after work, not as a session.

### Write down what you're worried about (literally)

Sounds silly, but the evidence is solid: 15 minutes before bed, you write down what worries you and next to each one a concrete action for tomorrow. Your brain stops ruminating at 3 AM because there's already a plan. It's functional brain dump.

When it's time to lower the goal

If you've spent 3 weeks with low HRV, bad sleep, high resting HR and workouts feel harder — scratch the A race and plan a later one. It's not weakness, it's strategy. People who insist and race in bad shape end up with 6 weeks of post-event injury (and nobody reads the lessons-learned doc you left).

Your fitness won't be lost in 4 weeks of reduced volume. What you lose is 8 months when you get injured running with a collapsed nervous system.

Actionable summary

Sleep is metric number one: don't negotiate 7-8h.

Life stress counts as training stress; add both when planning.

Drop intensity before dropping volume when you're cooked.

Low HRV + high resting HR = red flag for 7-10 days.

If the A race falls in a bad life period, postpone it. Fitness doesn't disappear.

When your body is adapting to life, you can't ask it to also adapt to training. One thing at a time.