Weekly Roundup: How Your Brain Controls Your Fitness, Optimism for Reduced Dementia Risk, and Defining Wellbeing

Some fascinating topics this week — first up a surprising piece of research that shows just how much control you brain has over your fitness, followed by how optimism reduces dementia risk, and finally how to define wellbeing — which has proved trickier than you may assume.

You Brain Controls Your Fitness

As many of you already know I am an active sportsperson competing in masters athletics racing the 400m, 800m, and 1500m locally and internationally. You will also have ready many times in various of my posts how exercise has multiple benefits on brain function and brain health. But you may be, and I was, surprised to hear that the brain controls physical fitness not just the other way around.

By that I mean we know that exercise triggers multiple positive benefits and releases various biological transmitters that trigger positive adaptations in multiple areas in the body and brain.

This means that exercise, for example, also up regulates brain plasticity, simply put, it helps your brain grow. But the majority of fitness we consider a physiological aspect. The cells in our muscles become more efficient and our muscles grow and become adapted to the specific exercise patterns. When we talk about getting fit — we do not mean the brain gets fit.

[embed]How Exercise Helps New Brain Cells Grow Ok, I know we all know that exercise is good for us. Many of you also know that I have reported multiple times over the…andyhab.medium.com

But new research shows something different. The brain also seems to control fitness — a small region in the brain if “switched off” will inhibit endurance improvements, and constantly switching this on will also increase endurance performance past normal levels!

This research out of UT Southwestern in Dallas, USA, investigated a pathway already identified in an area called the Ventro Medial Hypothalamus (VMH). The hypothalamus is a small but key region that maintains homeostasis (i.e.body temperature, etc.) by regulating vital automatic, emotional, and hormonal functions.

This research was in mice, it must be noted, but the results are nevertheless fascinating. This research got mice “working out” on a mouse treadmill and observing and measuring activity here. In the Hypothalamus a group of neurons called the SF1-producing neurones became increasingly active as these mice did their workout.

This seems to act as a neural memory of the exercise and drives the body’s long-term adaptations. To see if this was the case the researchers conducted two further experiments. One in which they blocked these SF-1 neurons and the results of this was that the mice made no endurance gains! Their workouts were completely ineffective. So it wasn’t the physiological adaptions in muscles, heart, and lungs that was helping them get fitter (or not only).

In the second experiment they stimulated these neurons to see if this would have an effect. And it did have a dramatic effect — this allowed the mice to continue improving endurance fitness with no additional physical stimulus!

This is surprising because it removes the physical characteristic of exercise. Although obviously there always was a brain- body interaction this takes this to another level — your body is unable to adapt without this critical interface. Your brain is controlling your physical fitness.

There, is, however, also another consideration. You may find it appealing to now find a way to simulate your SF-1 neurons in your hypothalamus — but it could also be that exercising itself is the best way to train these and stimulate these.

This shows just how much we have a brain-body system not a brain and a body system.

And this shows fitness is in the brain, it is not necessarily in the mind — but something else in the mind has been show to lower dementia risk.

Optimism Lowers Dementia Risk

We might assume that optimism is related to many positive outcomes in life if not of simply being happier. But dementia seems to be a risk factor for many people and now researchers have being able to quantify how optimism reduces our risk of dementia.

[embed]The Power of Positivity Why being positive might energise your organisation!leadingbrainsreview.substack.com

Säde Stenlund and colleagues of Harvard analysed data from 9,071 cognitively healthy elderly individuals (average age at the outset was 74) — there were then follow ups over the next fourteen years. Optimism was rated using the Life Orientation Test-Revised.

What did they find?

They found that optimism reduced dementia by 15% for each standard deviation from the norm. Meaning there is also a dose-response relationships i.e. the more optimistic you are, the lower your dementia risk.

This was the case across all demographics and races. And it should it should be noted that they also controlled for depression — this means this is not just about “not being depressed”. It is being optimistic that helps.

There are likely multiple reasons for this some of which I cover in my previous article, above, “The Power of Positivity”, such as reduced stress hormones.

You may, however, counter that optimism is a personality trait and if you don’t have it, bad luck. Not so. Optimism is only 25% heritable and the rest is shaped by the environment and attitudes. These can be changed by cognitive reframing, and focusing on the positive vs the negative, the glass half-full principle.

And that is generally good for your wellbeing. On the topic of this, we may all intuitively understand wellbeing — but actually nailing down a clear description of this has been difficult. But now there seems to be a consensus.

What is Wellbeing?

As I said wellbeing sounds intuitive but once we try to nail it down precisely it becomes problematic. This is important because it means that when we or researchers talk about wellbeing we may be talking about different things.

To solve this problem an international group of academics has conducted a study with 122 experts across 11 disciplines. They found consensus on 19 dimensions (75%+ agreement) and almost unanimous agreement (90%+) on six dimensions.

1. Meaning and purpose — feeling life is worthwhile and goal‑directed
2. Life satisfaction — overall evaluation that your life is good
3. Self‑acceptance — positive and non‑judgemental view of self
4. Connection — close, caring relationships with others
5. Autonomy — feeling in control of choices and self‑expression
6. Happiness — frequent positive mood and cheerfulness.

It is also important to note that

• They also separate wellbeing from illness including mental illness
• They also separate drives from definitions. So, for example, physical health and income may also drives welling to a degree.
• This is not just about feeling good, thought that is an important part of it. Life has ups and downs but being ably to manage these downs is just as important.

My regular readers will know that this is all included in the SCOAP model and we argue that SCOAP is all you need because either includes 1, 3, 4, and 5 in the above list and SCOAP satisfaction leads to fulfilment of 2, and 6, in the list above.

https://leadingbrainsreview.substack.com/p/scoap-an-introduction

So this supports our thesis of SCOAP — a reminder you can sign up for a free online course here.

With that wishing you optimism, and high wellbeing this Sunday.

References

Kindel M, Post R, Grose K, et al. Exercise-induced activation of ventromedial hypothalamic steroidogenic factor-1 neurons mediates improvements in endurance Neuron, 2026; 0 https://doi.org/10.1016/j.neuron.2025.12.033

Säde Stenlund, Hayami K. Koga, Peter James, et al. The Bright Side of Life: Optimism and Risk of Dementia Journal of the American Geriatrics Society 08 April 2026 https://doi.org/10.1111/jgs.70392

Iasiello, M., van Agteren, J., Ali, K. et al. A Delphi consensus study on the dimensions of positive mental health Nat. Mental Health (2026). https://doi.org/10.1038/s44220-026-00617-5