What if one of the biggest factors affecting your energy, recovery and long-term health wasn’t your training or nutrition… but the light you’re exposed to every day?
Most triathletes spend hours dialling in their fuelling, sessions and recovery protocols. But modern life has quietly changed something fundamental to human biology. We now spend around 90% of our time indoors under artificial lighting that is very different to the sunlight our bodies evolved with.
In this fascinating episode, Advanced Sports Dietitian Taryn Richardson sits down with Professor Glen Jeffery, a neuroscientist from University College London and one of the world’s leading researchers on how different wavelengths of light influence our biology.
Professor Jeffery explains how light interacts directly with your mitochondria, the tiny energy factories inside your cells. And why certain types of light may influence everything from energy production and inflammation to recovery, metabolism and ageing.
You’ll also hear why athletes might be using red and infrared light the wrong way, and why the biggest benefits could actually come after hard training sessions rather than before.
If you’ve been curious about red light therapy devices or wondering whether they’re worth the investment, this episode will help you separate real science from marketing hype.
And if you want the full deep dive specifically for athletes, check out the brand new Red Light Therapy Masterclass here: https://www.dietitianapproved.com/redlighttherapy
In This Episode We Discuss
Why light is far more than just something that helps us see
The surprising role of mitochondria in responding to light exposure
How modern LED lighting may be quietly impacting metabolism and health
The difference between short wavelength light vs long wavelength light
Why sunlight contains critical wavelengths most indoor lighting lacks
The link between light exposure, inflammation and blood glucose regulation
Whether red light therapy can actually improve athletic performance
Why athletes may benefit more from post-training light exposure for recovery
The problem with many expensive red light therapy devices
Simple, low-cost ways to improve your daily light environment
Key Takeaways for Triathletes
Mitochondria respond directly to certain wavelengths of light, influencing energy production.
Long wavelength light (including infrared) may help reduce inflammation and support cellular recovery.
Athletes are already highly efficient metabolically, so red light therapy may have limited benefits before exercise.
The biggest opportunity may be after hard sessions, when mitochondria are stressed and recovery is needed.
Many commercial red light devices deliver far more energy than necessary, meaning more is definitely not better.
About the Guest
Professor Glen Jeffery, PhD
Professor Glen Jeffery is a neuroscientist at University College London and a leading expert on how different wavelengths of light affect cellular health and biological function.
Chapters:
00:00 – The surprising role of light in human health
03:00 – The spectrum of sunlight explained
05:00 – Why mitochondria are the key to energy production
08:00 – The problem with modern LED lighting
11:00 – How indoor environments may influence metabolism and inflammation
16:00 – The benefits of long wavelength light
20:00 – Can red light therapy improve recovery and health?
21:00 – Simple ways to improve your light environment
29:00 – The explosion of red light therapy devices
30:00 – Why athletes may not benefit before exercise
32:00 – Where red light may actually help athletes recover faster
35:00 – Practical advice for athletes experimenting with red light therapy
37:00 – The potential risks of overusing red light devices
If today’s episode sparked your curiosity about how light impacts recovery and performance, dive deeper with the Red Light Therapy Masterclass for Athletes here:
https://www.dietitianapproved.com/redlighttherapy
Other Links & Resources
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The Triathlon Nutrition Academy® is a podcast by Dietitian Approved®. All rights reserved.

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