Dr Rajat Chauhan

Day 131. Feel dizzy or lightheaded running in heat (Part 9)

When running in heat, feeling dizzy or lightheaded is not random.

In heat:

⬆️ Blood to skin (cooling)
⬇️ Blood to brain
⬇️ Blood volume (sweat loss)

Add shallow breathing → ⬇️ CO₂ → ⬇️ blood flow to brain

Result: Dizziness & Lightheadedness

What to do:

✅ Slow down immediately
✅ Cool the body
✅ Hydrate with electrolytes
✅ Breathe deeper

The body signals before it breaks. So, listen.

Keep miling and smiling.

Day 130. Why Breathing Matters More in the Heat (Part 8)

In heat, most runners: Pant, i.e. take shallow rapid breaths. This reduces efficiency.

Problem:

❌ Heat increases ventilatory demand → shallow breathing worsens fatigue

❌ Over-breathing, i.e. Hyperventilation reduces CO₂ → negatively affects oxygen delivery to muscles (Bohr effect) → Higher heart rate & More fatigue

Solution:

✅ Slow breathing improves vagal tone (parasympathetic activation)

✅ Diaphragmatic breathing improves ventilation efficiency

✅ Controlled rhythm

Breath = regulation

Use it.

Keep miling and smiling.

Day 126. Pace Lies In The Heat (Part 4)

Why heart rate matters more than pace in heat

In hot conditions, heart rate rises even at the same pace. This is ‘Cardiovascular Drift’.

More blood → skin (cooling)
Less blood → muscles

So your heart works harder

✔ Same pace ≠ same effort
✔ Rising HR = warning sign

👉 Slow down when HR climbs

Don’t chase pace. Listen to your body.

Keep miling and smiling

Day 125. Why Humidity Is More Dangerous (Part 3)

Why 35°C with humidity is worse than 40°C dry heat

It’s not just heat. It’s heat + humidity.

Your body cools by evaporation. Not sweating.

In dry heat → sweat evaporates → you cool

In humidity → sweat drips → cooling fails

Result:

Rising core temperature
Reduced blood to brain & heart
Fatigue + confusion

With adaptation:

↑ Plasma volume
↑ Sweat efficiency
↓ Heart rate

Don’t just check temperature. Check humidity.

Keep miling and smiling.

Day 123. Hydration Mistakes In Summer - Part 1

“Drink more water” is not always the answer. Overhydration can lead to *’hyponatremia’
(low sodium levels).

As highlighted by Professor Timothy Noakes in ‘Waterlogged’, Drink to thirst.

Also remember: Hydration ≠ just water

You lose ‘electrolytes’ in sweat. So replace both: Water + salts

Simple options: Lemon water, Buttermilk, Salt + water

The body knows. Listen.

Keep miling and smiling.