W8 - Heat Acclimatisation Strategies Flashcards
W8 - Heat Acclimatisation Strategies
How long does it take for most people to acclimatise to the heat?
7 days, but the adaptations start to occur after a few days. HR, Core temp and skin temp ↓, sweating rate ↑ as does our exercise capacity - lowering the starting point (core body temp) / tolerance for heat gain. This is proportional to a person’s fitness, the fitter you are, the better the adaptation, plus can acclimate faster and retain adaptations for longer. To benefit from this need stimulation, ↑ body temp - can wear more clothes, hot baths, saunas
What happens to the onset and rate of sweating and the onset of skin blood flow if we’re acclimatised and have a lower core body temp?
• The on set and rate of sweating onset is reduced
• The on set of skin blood flow increase is reduced
Do acclimatised people lose more electrolytes and sodium, and do they sweat more or less?
They lose less and sweat more
There are 2 acclimatisation protocols, constant stress and constant strain - what’s the difference?
Constant stress - keep workload, air temp or relative humidity (HR) the same but ↓ the strain (core temp, HR etc). Constant strain - keep core temp, hr etc the same but ↑ the strain. Probably wouldn’t do all 3, one at a time eg simply ↑ RH leaves other two the same
We would generally be preparing athletes for hot and dry condition or hot and humid. What’s the difference?
Hot and humid, can’t ↓ temp as easily. Therefore see skin and core temp (& HR) continue to ↑ where hot and humid, ↑ a little but then plateaus. However > sweat response in hot humid environs. Whatever trying to do try to mimic environment going to
How quickly does acclimatisation/ acclimationtake and acclimatisation decay?
7 days to acclimatise/ acclimate, approx 3 weeks to decay, core temp longer but can reacclimate very quickly, eg two days
Behavioural thermoregulation is our most effective tool at our disposal i.e. making us feel cooler in the heat eg sitting in the shade. Detail 5 cooling modalities that we could use in sport. Most of these can be done as pre-cooling and per cooling strategies
• Cold Drinks(10-24°C)
• Ice Slurry(0°C)
• Cold/ice towels(0°C)
• Cold/ice hat(0-4°C)
• Fans (Highspeed, close proximity) • Cold Water Immersio (8-15°C or 10-15°C but not super cold) up to 20 mins (sport)
What’s the aim of pre cooling & what are the 3 benefits?
• Reduce Tcore prior to competition, without dramatic < in
muscle temperature
• Increase heat storage capacity
• Improve cardiac function
• Improve performance in the heat
What does per cooling mean and what are the benefits?
Maintain a lower Tcore during an event
• ↓ increases in Tcore
• Improve cardiac function
• Improve performance in the heat
• Improve perception of fatigue and heat
What are the most efffective pre and per cooling strategies?
PRE:
• CWI – Core and peripheral
• Mixed-methods approach
PER:
• Cooling vest
• Fans and water
What are the 5 aims of post cooling?
• Reduce cardio vascular strain
• Relieve ANS fatigue
• Reduce inflammation
• Improve muscle recovery post-event
• Reduce muscle soreness
• Decrease core temperature
• Mitigate heat stress symptoms
Most effective time and temp for post cooling using CWI?
• 11-15 minutes
• Medium immersion:
• 11 and 15°C
