How long is the best time to do aerobic exercise every day

Let me give you the most practical conclusion first: For most healthy adults who have no special exercise goals, doing 30 to 60 minutes of moderate-intensity aerobic exercise every day is the most cost-effective choice that takes into account both benefits and safety. But this number is never a one-size-fits-all rule. For people who want to lose fat, prepare for competitions, and recover after surgery, the adaptation time can vary by two to three times. It’s really hard to stick to a certain number.

I went to the gym with a friend to find a personal trainer a while ago, and I saw two coaches arguing over this matter. The old-school coach who has been practicing for 20 years said that you need to walk slowly for an hour every day to nourish your heart and lungs, which will not hurt your joints and is suitable for ordinary people. In fact, both of them are right, but the people they are suitable for are fundamentally different.

You can actually find the corresponding reference by looking at the WHO's public exercise guidelines. Adults aged 18 to 64 should save 150 minutes of moderate-intensity aerobics every week, which equals about 30 minutes a day. This amount is not determined by experts, but is a conclusion drawn from long-term tracking of large samples: it will neither fail to improve the heart and lungs and improve insulin sensitivity because of too little exercise, nor will it cause additional burden on the joints and immune system because the duration is too long. I used to have a colleague with high blood lipids. He walked briskly around the perimeter of the office building for 35 minutes during his lunch break every day. The pace was not fast, and he could gossip with his colleagues while walking. He persisted for 3 months and then had a physical examination. His blood lipid index returned to the normal range. He did not delay picking up his children from get off work, and he did not feel that exercise was a burden at all.

If the core goal of your exercise is to lose body fat, many bloggers who focus on aerobic training will recommend that you extend the duration to 45 to 90 minutes and control the intensity at about 60% of your maximum heart rate, which is the level where you can speak normally but cannot sing loudly. This range has the highest proportion of energy supply from fat. But there is also a completely opposite view here. Most strength training practitioners will remind you that steady-state aerobic exercise for more than 45 minutes will increase the probability of muscle decomposition. It is better to split the time into 20 minutes of fast walking in the morning + 30 minutes of slow walking after strength training in the evening, which can not only remove fat but also preserve muscle mass. When I was preparing for a half-marathon last year, I tried running 50 minutes of steady-state running every day for two consecutive months. I did lose 2 points of body fat, but I also lost 5 kilograms in bench press weight. Later, I reduced the running time to 30 minutes, and then added 20 minutes of upper body strength, and then slowly increased the weight back. After trying it myself, the latter is indeed more suitable for runners like me who don’t want to lose muscle.

If you are a novice who has just started exercising, or has an old knee injury, or is over 60 years old, there is no need to meet the 30-minute threshold. Walking slowly for 10 minutes three times a day, doing Tai Chi, or doing Ba Duan Jin are all effective exercises. My grandma is 72 years old. She has bone spurs in her knees and cannot walk long distances. She walks downstairs for 15 minutes in the morning, noon and evening every day. She even stands and chats when meeting old neighbors. She only exercises for just over 30 minutes a day, and her blood pressure is controlled more stably than any health supplements she takes. On the contrary, I came across a netizen a while ago who didn’t exercise at all. After seeing others saying that running 5 kilometers a day was good, he ran for a week and developed effusion in his knees. He had to lie down for half a month before he could walk normally. The gain outweighed the loss.

If you are really busy and can't spare 30 minutes, don't worry at all. Many studies in the past few years have confirmed that 10 minutes of high-intensity intermittent aerobics, such as jumping jacks, burpees, and short-distance sprints, interspersed with it every day, as long as the heart rate can be raised to more than 80% of the maximum heart rate, will have the same cardiopulmonary improvement effect as 30 minutes of moderate-intensity aerobics. When I was working on a project last week, I stood up and did leg raises + jumping jacks for 3 minutes every hour of work. I saved up 15 minutes a day. I went to run 5 kilometers on the weekend. My pace didn’t drop at all. My resting heart rate remained at 58. I didn’t lose my aerobic status just because I didn’t do it for a few days.

To put it bluntly, is there any absolute "best time"? To put it bluntly, it depends on your own exercise goals, physical tolerance, and the free time you can squeeze out every day. Don't compare the length of time with others, and don't force yourself to make up the numbers despite physical discomfort. The length of time that you can stick to for a long time is the best for you. Oh, by the way, if you have a fever that day, are sore, and are so tired that even climbing the stairs is a struggle, then it’s okay even if you don’t exercise at all that day. Exercise is supposed to add points to your life, not to add more KPIs to you, right?