In this episode, Dave chats with Professor Glen Jeffery, a neuroscientist at University College London’s Institute of Ophthalmology, whose research investigates how light, particularly long-wavelength red and infrared, influences human health, metabolism, and ageing.

Glen Jeffery is recognised as one of the world's leading researchers in exploring how light interacts with our bodies.

Glen explains how sunlight penetrates the body, enhancing mitochondrial function, improving vision, and even boosting motor skills like grip strength. He warns that modern LED lighting, while energy-efficient, can harm metabolic health compared to incandescent bulbs that emit beneficial infrared light.

They examine the public health consequences of our “infrared starvation,” the role of mitochondria in ageing, and the unexpectedly affordable potential solutions, such as rethinking indoor lighting and spending 20–30 minutes outdoors. Glen makes comparisons to historical issues like scurvy, emphasising the need for urgent policy reforms before our ageing, indoor-bound populations face worsening health crises. Practical advice includes seeking more natural light, using infrared-rich lighting where feasible, and adopting lifestyle changes that incorporate movement and sunlight exposure.