Dr. Andrew Huberman, Ph.D. is a Professor of Neurobiology and Ophthalmology at Stanford University School of Medicine. His lab focuses on neural regeneration, neuroplasticity, and brain states such as stress, focus, fear, and optimal performance.

In this episode of the Huberman Lab Podcast, learn all about water: its structure, how it is used by the cells and tissues of our body, how much water we each need to drink, and when in order to optimize our mental focus and physical performance, how weather affects our water use and intake, and so much more. 

Rare characteristic: when water is in its solid state (ice), it’s less dense than it is in its liquid state (this is why ice floats in water)

• If this weren’t true, life wouldn’t exist in the same way – for example, the bottom of the ocean would be covered in ice

Structured water: in the presence of some solids or liquids, the configuration of water changes

• Positives and positives attract and form stronger bonds than ‘regular’ water
• Some people believe the water in the body is structured and now it’s a marketing trend (more on trend below)

Water is one of the best solvents that exists

• Molecules can be hydrophobic (don’t dissolve well) or hydrophilic (dissolve more easily)

Temperature and alkalinity (pH) of water are important determinants in how your body uses water – we are somewhere between 70-90% water

Every cell in the body requires water (water enters cells through diffusion or aquaporin channels)

• Aquaporin channels are used when water needs to enter or rapidly release through cell
• Bones and ligaments are the only areas in the body without aquaporin channels

The truth about bottled alkaline/pH water: pH in the body is highly regulated without outside intervention – there’s no physiological need to drink pH water unless you have

• What is true is that all water is not created equal and this can differentially affect absorption, which some are more sensitive to

Most biological processes in the body involve bonding between water and proteins: once water is in cells it’s incorporated into different proteins depending on how hydrophilic or hydrophobic they are

Free radicals can damage cells because they are free electrons, not bound to anything, and can interact with the molecular structure of proteins and change them which can cause damage to cells

Antioxidants: bind free radicals or repair bonds between cells so they’re no longer undergoing bad conformations

• Water can act as an antioxidant under the right conditions

Cells of the kidney and gut are under strong regulation of the circadian clock gene – for the first 10 hours after waking, the kidney is working hard to filter fluid then efficiency reduces

To reduce nighttime urination frequency: (1) hydrate sufficiently during the day; (2) reduce fluid intake at night; (3)don’t chug water! sip slowly, rate matters

Informal ways to measure dehydration: (1) if you can pinch the skin on top of your fingers and it doesn’t return for more than 5 seconds; (2) press down on the nail, if the color doesn’t return to normal within a few seconds

Amount of fluid (not just water) most people need at rest: consume 8oz of fluid for every hour you are awake for the first 10 hours of your day – this can be consumed as total volume over the course of the day

• Not accounting for extreme weather or extreme sports

Water requirement for exercise: you’ll want additional fluid – follow the Galpin equation, your body weight (in pounds) / 30 = # of ounces to consume every 15 minutes

• For performance’s sake, sip fluid, and don’t chug
• If you sweat a lot of in heat, increase by about 50-100%

Thirst is a reasonable guide for assessing hydration but thirst doesn’t keep up with hydration needs so can put you behind

• Ideally consume fluids that don’t contain caffeine or other diuretics

When we have fluid in the gut, cells are well-hydrated and the bladder has a fluid, there’s an elevation in sympathetic nervous system activity via (1) mechanical stretch receptors; (2) chemical signals (movement of water across aquaporin channels)   

Contaminated tap water can negatively impact fertility in males and females by causing endocrine disruption (ovarian function, spermatogenesis, fertility outcomes)

• The higher the concentration of magnesium and calcium in the water, the higher the pH
• Disinfection byproducts (remnants of disinfection treatment) can also impact the pH of the water

Know the water in your zip code: google your zip code + water analysis – you’re looking for fluoride levels in water (high fluoride can negatively impact thyroid stimulating hormone)

• Even 0.5mg/L can disrupt thyroid function

The hardness of water: higher magnesium and calcium-containing water may not taste as good but can have small reductions in the risk of cardiovascular disease

• Possibly because the elevated pH is more readily absorbed and more favorably impacts the hydration of cells

Zero cost option to filter water: draw 1-5 gallons of water and let it sit uncapped at room temperature for one day or half day so sediment falls to the bottom; then, pour our top 2/3 and drink

Cold exposure (11 minutes per week, up to the neck) has been shown to increase brown fat which increases metabolism and the ability to feel comfortable in cold temperatures

• You want the water to be cold enough that you’re uncomfortable and don’t want to stay in, but the temperature is safe enough to do so

Benefits of cold water exposure: increase in catecholamines (benefits mood and well-being), sexual satisfaction (probably from increases in testosterone in men and women), reduction in anxiety, reduction in waist circumference in men, reduction in abdominal fat in men

Sample protocol: 2 minutes of deliberate cold exposure/water immersion up to the neck + 5x per week, 30 seconds of deliberate cold exposure with a cold shower

Other Resources

• Using Deliberate Cold Exposure for Health and Performance
• ClearlyFiltered Pitcher
• Berkey Filters
• Molecular Hydrogen