Beyond Hot Flashes: How Heat Impacts Health & Longevity

How heat impacts health is the question today. Is heat more conducive to health benefits than cold? Do results differ for men vs women? I dive into this topic today with the author of a new book about how heat makes us stronger. 

Good news for this summer-loving podcast host!

My Guest:

Bill Gifford has written about health, performance, and longevity for more than 20 years. He is coauthor of the #1 NYT bestseller Outlive, with Dr. Peter Attia, and author of Hotwired: How the Hidden Power of Heat Makes Us Stronger. He lives with his family in Salt Lake City, Utah.

Questions We Answer in This Episode:

• [00:08:40] Why would exposing yourself to heat like sauna or hot environments actually be good for your health?
• [00:15:21] What does science really say about sauna use and long-term health?
• [00:17:46] Are cold plunges and ice baths as beneficial as sauna exposure?
• [00:36:07] Is there really such a thing as “sweating out toxins”?
• [00:43:24] What happens to heat tolerance as we age?

How Heat Impacts Health and Why Sauna May Support Longevity

Heat exposure may impact:

• Heart health
• VO₂ max
• Longevity
• Physical resilience

Heat exposure may provide both physiological and psychological benefits, including stress relief and recovery.

Heat vs. Sauna vs. Infrared: Does the Type Matter?

• Many people focus on specific methods like infrared sauna, but research suggests heat itself is the key factor.
• In some cases, hot baths may raise core temperature more effectively than saunas.

Sauna and Cardiovascular Health

• Frequent sauna use was associated with lower cardiovascular mortality.
• People using saunas multiple times per week had dramatically reduced risk of heart attack and stroke.
• Sauna may also offer protective effects against Alzheimer’s disease.
• Sauna creates a physiological response similar to light-to-moderate exercise.
• How the body responds in saunas:
  • • Increased heart rate
    • Increased blood flow to skin
    • Vasodilation
    • Sweating for cooling

Why Heat Can Mimic Exercise

• Sitting in a sauna triggers cardiovascular responses similar to mild exercise.
• However, one major component of exercise is missing: Muscle activation

Heat exposure can support cardiovascular health but cannot replace strength training or physical activity.

Heat vs Cold Therapy: What the Research Really Shows

• Cold exposure mainly helps restore body temperature after heat stress.
• Using a cold plunge immediately after strength training may reduce muscle growth adaptations.

Heat Training & VO₂ Max Improvements

• Heat training may also produce adaptations similar to altitude training, including:
  • • Improved oxygen delivery
    • Increased hemoglobin levels
    • Improved endurance capacity
• This suggests heat training is a more accessible alternative to altitude training.

Hydration & Electrolytes During Heat Exposure

• Heat exposure can cause significant fluid loss—sometimes up to a liter of sweat per hour.
• Failing to replace fluids and electrolytes can lead to:
  • • Fatigue
    • Headaches
    • Hangover-like symptoms

The Surprising Science of How Heat Impacts Health and Longevity in Midlife

Does Sweating Remove Toxins?

• The liver and kidneys are the body’s primary detox systems.
• The idea that sweating detoxifies the body is widely promoted but not strongly supported by mainstream medical evidence.
• While research continues, there is no definitive evidence that sweating removes toxins from the body.

Heat Tolerance and Aging

• Heat tolerance tends to decline with age.
• Research shows fit older adults maintain better heat tolerance.
• Two factors that improve resilience:
  • • High VO₂ max relative to age
    • Regular heat exposure or heat training
• These adaptations can help older adults maintain sweating efficiency and heat resilience similar to younger people.

How about you? How do you feel heat impacts your health?

Connect with Bill:

• Instagram – @billgifford
• X – @billgifford