CoachingDIAGNOSIS

HEAT PERFORMANCE DROP — WHEN SUMMER WRECKS YOUR NUMBERS

Winter numbers look like a different rider than your summer numbers. On anything over 25°C your HR climbs 15 bpm, your power falls 10-20%, and efforts that felt controllable in March feel impossible in July. You assume you've lost fitness. You haven't — you've lost heat tolerance.

THE SHORT ANSWER

Most often, this is because skin blood flow redirects blood from working muscles to cooling — reducing power at a given HR. The fix: plan progressive heat preparation — match the exposure, recovery and safety plan to the event and rider.

WHY THIS HAPPENS

✗

Skin blood flow redirects blood from working muscles to cooling — reducing power at a given HR

✗

Fluid losses and excessive drinking can both compound an already difficult heat-management problem

✗

Core temp rise slows pacing as the brain protects against hyperthermia

✗

Sodium losses from sweat disproportionate for heavy sweaters

✗

No progressive exposure to conditions representative of the target event

✗

Poor clothing choices — dark kit, no ventilation, hot lids

✗

Over-pacing early — a 'normal' early-ride effort becomes a heat disaster 90 minutes in

WHAT TO DO ABOUT IT

Plan progressive heat preparation

Match the exposure, recovery and safety plan to the event and rider

Individualise food and fluid

Use representative field observations instead of one hourly volume or sodium dose

Rehearse cooling options

Test practical event-legal methods without treating comfort as a safety guarantee

Reduce the opening demand

Use power, heart rate, perceived effort and symptoms together rather than one universal cutoff

FREE DIAGNOSTIC

Plan hot-weather fuelling + fluids

Or apply for coaching →

WHAT THE EXPERTS SAY

John WakefieldWorld Tour coach, Bora-Hansgrohe; works with Primož Roglič and Jai Hindley

Wakefield coaches around internal load — the cost of a session to the rider, not just the watts on the screen. Heat is the clearest case: the same power costs more when it's hot, so the answer is a structured 10-14 day acclimation block and monitoring day to day, rather than forcing through and turning an adaptation week into overreaching.

Hear it: How Team Bora Build Endurance: John Wakefield on Ultra Cycling Training