How much exercise is enough? Enough for what? What are your goals?

It's always been a difficult question as we have many different reasons to exercise. Some move to build muscle for aesthetic, and ultimately psychological reasons. Some move for the sheer joy of it. Some to keep up with the kids. Some as even baseline fitness makes life so much easier. Everyone has their own reason.

But, if we reduce the question to 'How much do I need to exercise to live a long life?' Then we may have got an answer. For the mainly white, middle-class ex-healthcare workers in the study at least. The British Journal of Sports Medicine just published a paper snappily titled: Long-term resistance training with all-cause and cause-specific mortality: assessing dose-response and joint associations with aerobic physical activity. In which they studied 147 000 participants over 30 years to try and answer the question. This wasn't even a meta study, that was the size of their cohort.

Here's what matters: 
90 - 120 minutes of weekly strength training may be the sweet spot. That reduces your chance of dying from heart disease by around 20% and, even more encouragingly, from Alzheimer's by about 30%.

Other interesting takeaways include:
Longevity benefits level off after 2 hours a week. So you really don't need to be losing a huge part of your week to the gym.
Risk of cancer death is actually lower for people doing up to 30 mins of strength training than those doing 30 - 60 minutes. So more does not equal better.

These reductions are from strength training but the greatest benefits come from combining strength and cardio activities. That can reduce your all cause mortality by up to  a huge 45%. 

We've always been advocates of a mixed exercise routine. Unless you're an actual, career athlete, training for a specific event then your body really would be better off with some mixture of 'movement modalities'. Being able to cycle 200 km is great, as is bench pressing 200KG, but if all your training is focused on those singular types of movements and outcomes it seems like you may be leaving a lot of fun on the table. Ask any surfer, skater or mountain biker, the joy often resides in the balance.

Full study here (but you'll need to pay for access).