Palmar Cooling

Key finding: Stanford research showed 144% more pull-up volume over 6 weeks with palm cooling between sets.

Mechanisms:

• Palms contain AVAs (arteriovenous anastomoses) for rapid heat exchange
• Cooling palms quickly reduces core temperature
• Lower core temp delays CNS fatigue response
• Muscle enzymes work better at optimal temperatures

Key studies:

• Grahn et al. (2012): 144% more pull-ups over 6 weeks
• Heller & Grahn (2002): Palm cooling matches whole-body cooling
• Grahn et al. (2005): Increased bench press volume

Effect sizes:

• Training volume: Large (when heat-limited)
• Strength gains: Moderate (via increased volume)
• Endurance: Moderate (in hot conditions)

Limitations:

• Only works when heat is limiting factor
• Less benefit in air-conditioned gyms
• DIY methods work nearly as well as $1,000 devices

Critical: Use 50-60°F water, NOT ice. Too cold causes vasoconstriction and defeats the purpose.

Basic protocol:

1. Cool palms between sets (not during)
2. Use 50-60°F / 10-15°C water
3. Hold 30-90 seconds per rest period
4. Keep palm flat against surface

DIY methods:

• Frozen water bottle in thin towel
• Bowl of cool water + ice
• Metal dumbbell or barbell
• Wet towel from fridge

Common mistakes:

• Ice directly on palm (too cold)
• Cooling during sets
• Not cooling long enough

Known risks:

• Essentially none when done correctly
• Too-cold temps reduce effectiveness

Contraindications:

• Raynaud's disease
• Cold urticaria (cold-induced hives)

Interactions:

• None - compatible with all training

Ideal for:

• Anyone who overheats mid-workout
• High-volume training (bodybuilding, CrossFit)
• Hot gym environments
• Endurance athletes in heat

Skip if:

• Training in cold/AC environments
• Doing short, low-volume sessions
• Have Raynaud's disease

Best results with:

• Multiple sets per exercise
• Sessions 45+ minutes
• Compound movements

What to measure:

• Total volume (sets × reps × weight)
• Reps on later sets vs baseline
• Subjective fatigue mid-workout

Tools:

• Training log or app
• Infrared thermometer for water temp

Timeline:

• Immediate: Same-session improvement
• 4-8 weeks: Strength gains from added volume

Signs it's working:

• More reps on later sets
• Less mid-workout fatigue
• Feel cooler despite high effort

Best value: A $15 frozen water bottle works nearly as well as the premium devices. See heatdumping.com for product comparisons.

Premium devices ($900+):

• CoolMitt (~$995) - Stanford-affiliated, vacuum seal
• NICE ROCC (~$975) - USB-C rechargeable, 1.5hr battery
• Kühler (~$900) - No ice/water needed, week of battery

Mid-range ($50-300):

• Therabody RecoveryTherm Cube (~$199) - Hot/cold therapy
• Black Ice CulCan (~$50) - Portable aluminum, 60 min cooling
• The Narwhals - Passive cooling, no charging

DIY (equally effective):

• Water bottle (~$15) - freeze, wrap in towel
• Small cooler ($20) - keep water cold at gym
• Bowl + ice + water (free)

What to avoid:

• Ice packs directly on skin
• "Cooling gloves" without temp control

Free:

• Bowl of cool water
• Metal gym equipment

Budget ($5-50):

• Frozen water bottles ($15)
• Small cooler ($20)
• Black Ice CulCan ($50)

Premium ($900-1,000):

• CoolMitt, NICE ROCC, Kühler

Bottom line: Start with a frozen water bottle. Premium devices are for pro athletes or those who want convenience.

Researchers:

• Craig Heller, PhD - Stanford biologist, pioneer of palmar cooling research
• Dennis Grahn, PhD - Stanford researcher, co-developed cooling technology
• Andrew Huberman, PhD - Popularized the research widely

Reddit:

• r/fitness - Positive reports from those who try it
• r/bodybuilding - Popular for high-volume training

What people say:

• "Got 3 more reps on my last sets"
• "Game changer for summer training"
• "DIY bottle works great"

Common complaints:

• "Feels weird at first"
• "Doesn't help in AC gyms"

Pairs well with:

• High-volume training
• Caffeine (offsets heat from stimulants)
• Hot environments

Timing:

• Between sets, not during
• Most valuable in second half of workout

Less useful when:

• Training in AC environments
• Low-volume strength work (1-3 sets)