How to Optimize Hydration with Dr. Heather Logan-Sprenger
WHOOP Podcast
Mild Dehydration Shifts Metabolism to Carbs
Heather describes her research showing mild dehydration causes preferential carbohydrate use and earlier fatigue.
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. The two take a deep dive into one of the most underrated and often forgotten about 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 suffering from heat stroke mid–PhD on hydration, 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 the simple hydration strategies, how to calculate your sweat rate at home, and when electrolytes actually matter.
(01:07) Dr. Heather Logan-Sprenger Intro: Background in Sport & Physiology
(01:49) Training, Nutrition, & 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 & 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
(01:05:23) Outro
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