BBC Gardeners’ World Magazine Podcast · Immediate Media

Improve your sleep, with Dr Christine Blume

January 13, 2026·33 min·3 clips

Why your internal clock might be shorter or longer than 24 hours, shaping whether you're a morning lark or night owl.

This episode features Claire Venice from BBC Gardeners' World Magazine and sleep scientist Dr. Christine Blume from the University of Basel. Dr. Blume's research focuses on how natural light and environmental factors regulate our circadian rhythms and sleep. The conversation explores practical ways gardeners can use outdoor activity to improve their rest. The central biological clock in our brain, called the suprachiasmatic nucleus, generates a near-24-hour rhythm independent of environmental cues. Natural light is the primary "zeitgeber" that synchronizes this internal clock with the external world. Individual circadian rhythms vary, with early "larks" often having a slightly shorter cycle and night "owls" a longer one. A misaligned rhythm, like in shift work, increases risks for cardiovascular disease, metabolic disorders, and depression. Sleep architecture involves deep sleep dominating the first half of the night to reduce sleep pressure, while REM sleep and dreaming are more prevalent later. Dr. Blume identifies stress and modern indoor lifestyles with low daytime light and bright evening screens as major enemies of sleep quality. One key insight is that even on a grey, overcast day, outdoor light levels are orders of magnitude brighter than typical indoor lighting. Daylight exposure not only improves sleep by making people tired earlier but also has direct mood-lifting effects. Dr. Blume's ongoing research hypothesizes that exercising outdoors is more beneficial for sleep than indoor activity due to the combined effects of light and nature exposure. She notes that warming nights due to climate change present a growing challenge for sleep, as behavioral adaptations like lighter bedding have limits. A surprising claim is that the common phenomenon of "spring fatigue" may not show a clear seasonal pattern when tracked repeatedly over a year, contrary to popular belief. For combating winter darkness, Dr. Blume recommends morning light exposure via a walk or a 10,000-lux therapy lamp, and a bedtime ritual like a warm foot bath, as science confirms cold feet hinder sleep. The ideal sleeping temperature is between 16-18°C to facilitate the body's necessary cooling process. She emphasizes that all sleep stages are important and advises against fixating on sleep tracker data, trusting the body to produce what it needs. The tone is conversational and educational, blending accessible science with practical, gardener-centric advice. Dr. Blume shares personal anecdotes, like keeping her window open even in minus-10-degree weather and her childhood love for growing yellow bush beans. Listeners interested in the science behind sleep and simple, non-pharmaceutical ways to improve it through gardening and nature will love this episode. Those seeking highly technical sleep research details or quick-fix solutions might find it too introductory.

As heard by us

A calm, useful listen that treats daylight, nature and sleep as closely linked.

BBC Gardeners World Magazine Podcast opens with a simple idea and sticks to it: gardens, daylight and sleep are tied together. Dr Christine Bloom, a sleep scientist from the Centre of Chronobiology at the University of Basel, makes the science feel plain and usable.

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Why you'd press play

If your evenings feel wired and your mornings feel thin, this is for you.

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