AMA #10: Benefits of Nature & “Grounding," Hearing Loss Research & Avoiding Altitude Sickness

KEYPOINTS

• 01

  Morning sunlight is the best-supported benefit of being outdoors

  Huberman says dozens if not hundreds of quality peer-reviewed studies support getting sunlight in your eyes early in the day to set your circadian rhythm. He calls it unequivocally supported: it raises daytime mood, focus and alertness, improves nighttime sleep, and benefits metabolism. The metabolic effect may be direct, but more likely it comes indirectly from better sleep.

• 02

  Light through glass or from a screen doesn't count

  You won't set your circadian clock by viewing the sun through a window or windshield, or by looking at an image of the sun on a screen. You don't need to catch sunrise. If you wake after the sun is up, go outside, face it, and blink as needed to protect your eyes, especially on overcast days. Late-afternoon light before sunset adds further benefit.

• 03

  SAD lamps are a fallback, not an equal

  If season, latitude or work schedule rules out morning sun, a bright seasonal affective disorder (SAD) lamp viewed for about 5–10 minutes, for example on the counter during breakfast, improves mood, focus and alertness and helps set the rhythm. Huberman stresses it is 'not nearly as effective' as real sunlight.

• 04

  Moving water may help through negative ionization

  A peer-reviewed literature, including work from a Columbia University School of Medicine laboratory, links negative air ionization near waterfalls, streams and similar moving water to benefits for circadian rhythm and some aspects of mental and physical health. Huberman hedges heavily: there 'does seem to be' benefit, 'perhaps' because of ionization. Home ionizer machines show some benefits in a few studies, but nowhere near those of time spent outdoors by moving water.

• 05

  Time in nature measurably improves health

  Dozens if not hundreds of studies show that 10–30 minutes outdoors, three to seven days a week, significantly reduces blood pressure and resting heart rate and improves sleep and mood. That holds across parks, streams, oceans and other natural settings. Huberman's answer to whether nature is good for you is 'absolutely yes.'

• 06

  Science struggles to isolate what makes nature work

  The scientific method relies on testable hypotheses, for example '30 minutes in nature three days a week improves mood and sleep.' But isolating single variables (green color contrasts, calming sounds, wildlife, smells from decomposing soil, air quality, ionization) means bringing people into bare lab rooms with pictures or recordings. Huberman argues that strips away the whole experience, including surprise, and understates nature's value. He thinks the method may never fully answer this one.

• 07

  Grounding has some evidence, but it is weak

  Grounding means placing bare feet directly on soil or grass. Proposed mechanisms include electron exchange with the earth's surface, rubber-soled shoes blocking that exchange, and the tactile sensation itself. Huberman notes few of these papers appear in top-tier journals and says there isn't enough quality science to conclude which mechanism, if any, explains the effects.

• 08

  Forest bathing started from controlled Japanese studies

  Huberman calls the Japanese forest-bathing studies 'pretty nice': people placed in forest environments for set periods showed better mental and physical health than controls. That prompted people to bring plants indoors. Plants look nice and may add pleasant odors, and Huberman suggests any benefit likely depends on how many there are and how much attention you pay them.