I am in no way prepared to become a gym bunny or exercise freak like some of my friends. How much do I really need to exercise to enjoy the benefits?The principle of least effort suggests that organisms, including complex ones like humans, instinctively navigate towards the path of least resistance.This is somehow hardwired into us. Many of us would rather accept a good-enough answer (think ChatGPT or Google AI mode) with little effort than pursue the perfect answer (in-depth analysis and rigorous fact-checking) at work or in our personal lives. What is the least amount of tax I can pay while remaining compliant? Specialists build careers out of this.Do you remember visiting the video store and spending half an hour physically browsing for movies? Very few envisioned a world where you’d choose your movie while lying on the couch and clicking on what Netflix “thinks” or “suggests” is right for you. It’s effortless, for sure, but hardly rewarding.We all know about exercise guidelines that suggest at least 150 minutes of moderately brisk exercise every week, including at least two days of resistance training.The recommendations always point to a cumulative exercise total over the course of a week. If you break this up over five or seven days, you may well land on a regimen that matches your friends who you so openly admire and despise.You may feel that 30 minutes a day is more than you’re willing to invest. Of course, I’d think you were mad, but let’s go with that assumption. You might argue that putting on training clothes, warming up and showering after, would take at least an hour of your day, excluding any commute to and from the gym.However, you don’t need to spend all your free time exercising, and you don’t even have to do it every day to enjoy the health benefits. You could, in theory, do it all over the weekend when you’re not as highly strung as a used Spanish guitar.The UK Biobank is a powerful medical database that tracks the health of about half a million adults, combining wearable fitness tracker data and medical records. That’s a powerful “screenshot” of how exercise correlates to better health outcomes.A Biobank study in 2024, which was published in Circulation, analysed data from 90,000 participants who wore an activity tracker. They were split into three groups: those who exercise regularly, those called “weekend warriors” and those who were inactive.The study found that if you pack 150 minutes of moderate to vigorous (take note of that second word) activity into one or two sessions as opposed to spreading it out across the week, you still enjoy the health benefits. Weekend warriors and regular exercisers had a lower risk of developing more than 200 different health conditions compared with inactive individuals. The point is that you can choose an exercise pattern that suits your routine.A second study published this year in the European Heart Journal tracked more than 96,000 UK Biobank participants for a week. They used precise, second-by-second movement data from the wearables to measure the exact intensity of the exercise. The researchers tracked when participants hit the vigorous “breathless” threshold, rather than just the total exercise time.They found that intensity is key. A higher proportion of vigorous physical activity, independent of total exercise volume, is strongly associated with a lower risk of eight major chronic diseases and all-cause mortality. Participants whose vigorous activity made up more than 4% of their total exercise had a 29%-61% lower risk of these diseases compared with those with no vigorous physical activity.In layman’s terms, brief bursts of vigorous exercise (enough to make you too breathless to speak comfortably), even just 60 seconds at a time, totalling as little as 15 or 20 minutes a week or a few minutes a day, are linked to substantial health benefits.This doesn’t mean you can train for a few minutes and call it a day; it means you can train less often and for shorter bursts than you thought you needed to, but you must be prepared to put in some effort. No-one is asking you to find more tax to pay, but your health return is proportional to doing the right thing.