2nd Feb 2026

Newsletter Monday

Hello Reader,

**“Men need to exercise twice as long as women”?

Let’s calm down.**

You may have seen the headline because it's not going away and it came up again in BBC Science magazine this month, 3 months after it was in The Guardian.

Which sounds dramatic.

Slightly alarming.

And, as usual, not quite how science works.

So let’s slow it down and look at what this research is actually based on — and what’s been lost in translation.

Where this headline comes from

​This claim comes from a large observational study using UK Biobank data — around 85,000 participants, mostly in their late 50s to early 60s.

That large number is usually a good sign. Big datasets reduce random noise and give more stable estimates.

Participants wore wrist movement sensors , the same technology used in fitness trackers and smartwatches, to objectively measure how often, how long and how intensely they moved, rather than relying on memory or self-report.

In this study, participants wore the device for around one week.

And here’s the key assumption: the researchers assumed that this one week of data reflected how active that person usually is.

They then followed participants for 7–8 years, tracking who went on to develop coronary heart disease or die.

That assumption matters.

A week of objective data is better than guesswork — but it’s still a snapshot, not a lifelong activity record.

And that shapes how confident we can be about the conclusions.

Relative risk: why headlines love it

Before we even get into exercise, here’s the simplest way to understand what’s going on.

If I buy two lottery tickets instead of one, I’ve doubled my relative chance of winning the lottery.

Sounds impressive.

My absolute chance of winning?

Still vanishingly small.

That’s the trick with relative risk.

It magnifies differences without telling you how big the actual risk was to begin with.

Now back to the study.

The headlines focused on this:

• women appeared to get a ~30% relative reduction in heart disease risk with around 250 minutes of weekly activity
• men needed closer to 500–530 minutes for a similar relative reduction

That’s where the “twice as much exercise” claim comes from.

But in absolute terms, the baseline risk of heart disease over several years in this age group isn’t huge.

So a 30% relative reduction might look like:

• about 10 people per 100 developing heart disease
• dropping to 7 per 100

That’s a 3-percentage-point absolute reduction.

Still meaningful — but very different from how the headline makes it feel.

Observational data: useful, but know what you’re looking at

This is an observational study, not an intervention.

That doesn’t make it bad science — but it does limit the conclusions you can draw.

And it’s important to know what type of data you’re being shown before reacting to it.

A personal example:

I've noticed that anyone driving aggressively behind me on the motorway often turns out, on closer inspection, to be:

• male
• under 30
• driving a VW Golf or an Audi A3

That’s observational data.

It does not mean those cars cause bad driving — or that age and sex magically produce annoying drivers.

It just means these things cluster together in the real world.

Exercise studies are similar.

People who move more also tend to differ in lots of other ways > weight, sleep, stress, alcohol intake, underlying health.

Researchers adjust for some of this, but they can’t adjust for everything.

So this is valid research — as long as you know what kind of evidence you’re looking at.

Are the findings still interesting? Yes

Once you remove the drama, the results are actually quite plausible.

We already know that:

• oestrogen has protective effects on the cardiovascular system, particularly before menopause
• there are sex differences in metabolism, vascular function and exercise adaptation

So the idea that women might see risk reductions at lower volumes of aerobic activity fits with what we already understand biologically.

What this study does not show is that men are doing something wrong — or that women can stop bothering once they hit a magic number.

What this actually means in real life

This study doesn’t rewrite the rulebook — and it doesn’t need to.

It reinforces a message that has held up well for a long time:

regular movement protects your heart.

Yes, the NHS (and every major health body) still uses 150 minutes per week as a sensible benchmark — not because it’s perfect, but because the evidence shows it’s:

• associated with meaningful health benefits

A lot of people of working age still fall short of that because life gets in the way.

So it's a good study, when it's understood.

The takeaway isn’t:

• “men need to panic”
• or “women can stop early”

It’s that moving your body regularly, in a way you can sustain, still does what we want it to do.

No stopwatch comparisons required.

See you next week.

Lynette