Podcast 355: How to Optimize Hydration with Dr. Heather Logan-Sprenger

This week on the WHOOP Podcast, WHOOP Global Head of Human Performance, Principal Scientist, Dr. Kristen Holmes sits down with dual-sport national team athlete and exercise physiologist Dr. Heather Logan-Sprenger to discuss one of the most underrated habits for human performance: hydration.

Dr. Logan-Sprenger shares how growing up in Northern Ontario, watching her dad water flowers and her cat grow winter fur, quietly planted the seeds for a lifelong fascination with physiology, stress, and adaptation. From competing for Team Canada in both ice hockey and road cycling to landing in the hospital with heat stroke, her experience and education show just how fragile — and adaptable — the human body really is.

Dr. Holmes and Dr. Logan-Sprenger identify what mild dehydration does to your metabolism, brain, and overall performance, and how hydration needs shift across the menstrual cycle. This episode will teach you hydration strategies, how to calculate your sweat rate at home, when electrolytes actually matter, and the biological markers that serve as helpful feedback.

Episode Chapters

01:07 - Dr. Heather Logan-Sprenger intro: Background in sport and physiology

01:49 - Training, nutrition, and hydration: Unpacking your body’s needs

08:06 - National-level athlete to PhD

10:51 - WHOOP podcast rapid fire questions

13:08 - Training at altitude: Hydration dos and don’ts

14:49 - The physiology of heat stroke

20:33 - Correlation between hydration and carbs while training

24:51 - How the menstrual cycle affects hydration

31:19 - Mechanisms of dehydration: What happens to the body

36:52 - Cognitive disadvantages of dehydration

38:56 - Dehydration’s effects on the cardiovascular and thermoregulatory system

40:35 - Dehydration’s effects on the brain

41:29 - Measuring your sweat rate as an athlete

45:39 - Essential habits to teach kids and athletes about hydration

49:20 - Overhydrating and mineral loss with hydration

53:45 - Debunking hydration myths

55:54 - Heart rate, lactate, and power output’s relationships to hydration

59:48 - Dr. Logan-Sprenger’s ideal hydration study: Mitochondrial hypoxia and metabolism