Two recent reviews from the British Journal of Sports Medicine come to a clear conclusion independently of each other:
 How fit you are is more important to your health and life expectancy than your body weight.

The focus here is on cardiorespiratory fitness (CRF) – i.e. the ability of the heart, lungs and muscles to supply the body with oxygen during exercise.

What is cardiorespiratory fitness (CRF)?

In simple terms, CRF describes how efficient your cardiovascular system is.
 It improves primarily through endurance training such as running, cycling, swimming or brisk walking.

In studies, CRF is often measured using exercise tests or VO₂max – in practice, it is simply shown by how long, how intensively and how economically you can movewithout tiring early.

Study 1: Fitness beats BMI

The first analysis examined almost 400,000 people and compared mortality risks on the basis of fitness level and body weight.

Central result

  • Fit people had a low risk of dying – regardless of whether they were of normal weight, overweight or obese.
  • Unfit people had a significantly higher risk – even if they were of normal weight.

In other words:

A slim but untrained person is statistically more at risk than an overweight but fit person.

Particularly clear:

  • Low fitness doubled the risk of premature death

This was true in all weight classes

Study 2: Fitness protects – almost always and everywhere

The second paper summarized results from almost 200 studies with over 20 million participants summarized.

The key message: The better the cardiorespiratory fitness, the lower the risk of

  • premature death
  • Cardiovascular diseases
  • Type 2 diabetes
  • Stroke
  • Many chronic diseases

The decisive factor:

  • This protective effect was shown in healthy people as well as in people with pre-existing conditions

Already Moderate improvements in fitness had measurable effects

Why CRF is so crucial

Cardiorespiratory fitness affects many systems simultaneously:

  • Heart works more efficiently
  • Blood vessels remain more elastic
  • Metabolism improves
  • Inflammatory processes decrease
  • Increased resilience in everyday life

This makes CRF a very strong overall marker for health – significantly more meaningful than weight or BMI alone.

What does that mean for you?

1. focus on getting fitter – not just getting lighter

Weight reduction can be useful, but brings significantly lessif it is not accompanied by better fitness.

2. endurance training is a health lever

Just 2-4 units per week can:

  • measurably improve your CRF
  • significantly reduce your health risk

3. “Fit instead of slim” is evidence-based

This statement is not a lifestyle trend, but has now been very well scientifically proven.

Briefly summarized

  • Cardiorespiratory fitness is one of the strongest predictors of health and life expectancy
  • Unfitness is risky – regardless of body weight
  • Fitness can compensate for many of the risks of being overweight
  • The biggest health gain is not on the scales, but in training

💚

Want to know where you stand?

Make an appointment to determine your VO2 max and get personalized tips on how to increase it.
 Take a look at our offer or book a free online consultation.⠀

Sources:

Weeldreyer, Nathan & De Guzman, Jeison & Paterson, Craig & Allen, Jason & Gaesser, Glenn & Angadi, Siddhartha. (2024). Cardiorespiratory fitness, body mass index and mortality: a systematic review and meta-analysis. British Journal of Sports Medicine. 59. bjsports-2024. 10.1136/bjsports-2024-108748.
Lang JJ, Prince SA, Merucci K, et alCardiorespiratory fitness is a strong and consistent predictor of morbidity and mortality among adults: an overview of meta-analyses representing over 20.9 million observations from 199 unique cohort studiesBritish Journal of Sports Medicine 2024;58:556-566.

https://inscyd.com/article/vo2max-charts-by-age-gender-sport/