How temperature affects your health, healing, and brain

Why saunas, red light therapy, and outdoor exercise can help this winter

It is very cold outside and I have been sitting at a desk all morning. This has made me feel both mentally and physically tired - sluggish — stagnant. Despite the option to take a nap, I opted to go for a jog and broke out in a light sweat. As a result, I am now feeling revitalised and the chilly run sparked the inspiration for this article!

As we finally settle into proper winter here in New Zealand, it’s a good time to talk about something few people think much about — the effect of temperature on your body’s inner workings.

Did you know that raising your body temperature even slightly can increase the activity of your metabolism, your immune system, and even your brain chemistry? This is particularly relevant in winter, when most of us are colder, less active, and more prone to seasonal mood changes such as Seasonal Affective Disorder (SAD).

It’s also highly relevant for people with neurological conditions such as Multiple Sclerosis (MS) and Parkinson’s Disease (PD) — where using temperature wisely can help support healing, improve mood, and reduce symptoms.

How temperature affects your body

Most of the chemical reactions in your body — especially those run by enzymes — are sensitive to temperature. For many key enzymes, every 1°C rise in temperature speeds them up by about 6–12%. So even going from 37°C to 39°C can increase some processes by 20–30%.

Here’s what happens as your body warms up slightly:

• Mitochondria produce more ATP energy (your body’s fuel).

• Serotonin and dopamine levels rise — these are your “feel-good” brain chemicals.

• Immune cells become more active.

• Repair processes accelerate.

• Blood flows better — as we’ll explain in a moment.

Blood flow — why warmth matters

Your blood is very much like gravy — when warm, it flows smoothly. When cold, it thickens, becoming sluggish and more “sticky” — more like jelly.

In cold weather:

• Blood vessels constrict (narrow).

• Blood viscosity (thickness) increases.

• Clotting risk increases.

This is one reason why heart attacks and strokes spike in winter.Cold, thickened blood moving through narrowed vessels creates the perfect storm for cardiovascular emergencies.

Keeping your core and peripheral tissues warm — through movement, heat therapy, or simply better circulation — helps maintain smooth, healthy blood flow.

Exercise — the natural way to warm yourself

It should go without saying that exercise is the simplest and most natural way to boost internal temperature — and fast.

When you move your muscles:

• You generate heat internally.

• Mitochondrial activity increases.

• Blood vessels dilate.

• Blood becomes less viscous and flows more freely.

• Mood chemicals like serotonin and dopamine increase.

This is why after a brisk walk, bike ride, or workout — even on a cold winter’s day — you often feel clear-headed, warm, and energised.

For those with MS or Parkinson’s, appropriate exercise, done carefully and regularly, is one of the best therapies there is — and it naturally complements sauna and RLT.

Why this matters more in winter

In winter, most Kiwis:

• Spend more time indoors.

• Are more sedentary.

• Are exposed to less bright light.

• Have lower body temperature and circulation.

• Are prone to seasonal affective disorder (SAD) — linked to low serotonin and dopamine.

If you’re feeling sluggish, tired, low in mood, or your joints and brain feel stiff — this is not just “getting old” or “just winter.” It’s partly due to this slowing of your body’s core chemistry and circulation.

I was reminded of this very clearly in 1977, when I was in Sweden as the paramedic and trainer for the New Zealand Masters Athletics team. I was there during the Masters World Championships and while visiting Sweden's famous rehabilitation services. My host, Dr Atle Worhm, explained why the Swedes compulsively take off their clothes at the slightest ray of sunshine:

“We have dark and bleak winters, and they are very long. If we have a bad summer, we have more illness the following winter — including much depression. The effect is lasting. The quality of our summer affects our health during winter"

I never forgot those words. It perfectly illustrates how sunlight, warmth, and movement are not just "nice to have" — they are essential for human health, especially in cold, dark seasons.

Neurological conditions and temperature

For people with MS and Parkinson’s, temperature plays a special role:

In Parkinson’s:

• A slight rise in temperature helps boost dopamine production and improves motor function.

• Many PD patients feel more flexible and clear-headed after sauna or Red Light Therapy (RLT).

In MS:

• Heat must be used carefully. Too much heat (>39.5–40°C core temp) can temporarily worsen nerve conduction.

• But moderate, controlled heating — such as RLT or short, mild sauna — supports:

  • Mitochondrial function.

  • Mood (via serotonin and dopamine).

  • Tissue repair.

  • Fatigue reduction.

    
    

In both conditions, carefully used heat can help reduce symptoms, boost mood, and support resilience during winter.

Why Sauna and Red Light Therapy are so useful

Sauna:

• Creates a controlled, gentle rise in body temperature.

• Stimulates heat shock proteins → supports tissue repair.

• Increases serotonin and dopamine.

• Mobilises toxins and improves circulation.

• Helps keep blood flowing like smooth gravy — not cold jelly.

You can read my full guide here:https://www.garymoller.com/post/how-to-use-a-sauna-to-improve-your-health

Red Light Therapy (RLT)

I highly recommend adding Red Light Therapy to your home health routine. It is one of the most effective and natural ways to support:

• Mitochondrial function

• Mental clarity and mood

• Skin, hair, and nail repair

• Collagen production

• Healing inside the mouth

• Deep tissue regeneration — even reaching lung tissue and internal organs

I suggest looking at the Sohl Compact (or higher) as a reliable home-use option:https://sohl.global/collections/all-products/products/sohl-compact-sw60

If you use the coupon code GaryMoller10 you will receive a discount on purchase.

Important: machines cheaper or smaller than the Compact generally do not deliver the energy needed to achieve meaningful results in cases like yours.

For an overview of the many proven benefits of RLT, I encourage you to explore this resource:https://www.youtube.com/results?search_query=red+light+therapy

You can also read my overview of how mitochondria work here:https://www.garymoller.com/post/mitochondria-101-the-powerhouses-of-life

Suggested winter protocols

For general health and resilience (most people):

• Exercise:

  • Daily if possible — brisk walking, cycling, strength training.

  • Even 10–20 mins can have profound effects.

• Sauna:

  • 2–3 times per week.

  • Start with 10–15 mins at 60–75°C.

  • Gradually increase time and temp as tolerated.

• RLT:

  • 3–5 times per week.

  • 5–15 mins per area (face, neck, spine, joints).

For Parkinson’s Disease:

• Exercise:

  • 4–6 days per week — any form of movement is good.

  • Focus on whole-body, upright movement — to counteract the typical stooped, shuffling gait.See my article:https://www.garymoller.com/post/are-you-a-t-rex-walker

• RLT:

  • 4–6 times per week.

  • Target forehead, neck, upper spine.

• Sauna:

  • 2–3 times per week.

  • 10–20 mins at moderate temperature (avoid dehydration).

For Multiple Sclerosis:

• Exercise:

  • Light, regular exercise — within tolerance.

• RLT:

  • 3–5 times per week.

  • Target spine, muscles, neck.

• Sauna:

  • Short, mild sessions: 5–10 mins.

  • Lower temperature (50–65°C).

  • Monitor for any signs of temporary worsening and adjust accordingly.

Important caution:

• Always start gradually.

• Listen to your body.

• For MS, avoid prolonged high heat — the goal is to gently stimulate, not overheat.

In Finishing

As a Kiwi living in a free environment, I challenge you to welcome the winter season by doing things like saunas and RLTs, as well as staying active in the great outdoors. All of these things will help you a lot.

• Stay energetic.

• Keep your immune system sharp.

• Support your mood and brain.

• Keep your blood flowing freely — protecting your heart.

• For neurological conditions, carefully applied heat and movement can genuinely improve quality of life.

Medical Disclaimer:

This article is for general education. It does not replace personalised medical advice. If you have a health condition, consult your practitioner before starting new therapies, especially if you have MS, cardiovascular issues, or are on medications.