This is a question that does not have an easy one size fits all answer. Regular exercise is necessary for health, as it maintains and improves our circulation and breathing while working our musculoskeletal system. All of our joints have an optimal range of motion and the body is very much use it or lose it in function.
Specific exercise was not necessary when we had to hunt and gather our own food. The work in chasing down an animal and gathering plants for food provided plenty of natural physical activity. We still have activities of daily living today, but that is dwindling with time spent sitting in front of a computer screen, the vast variety of prepared food and modern gadgets, as vacuuming can be done with an automated device!
I’ve been asked many times in my career how much do you exercise or you must work out every day? The answer is I make an effort to be active daily. Anywhere between 20-60 minutes of some form of physical activity daily, is my commitment. It could be a walk, weight training, yoga, running, tai chi/qi gong or a spin class. Personally, I like walking to a specific destination or walking to get food, so it is like working for the food at least a little. Find out what motivates you to take that walk, hit the weights or do a few yoga poses- making it easy for yourself to complete the task regularly will build the habit. The key is to complete any amount of activity regularly- 5-10 minutes is better than nothing. It’s important to see yourself as someone who exercises regularly to take care of themselves. For the purposes of health and longevity, light to moderate intensity exercise is enough, which is also the healthy living guidelines of traditional chinese medicine.
Of course, once we get into a regular habit of exercise and have some specific goals, it becomes possible to overdo things. Injuries or lingering pain are usually a sign of overdoing exercise in terms of your current capabilities. Pushing through is generally not a good plan, since it typically makes the injury worse. Speaking from experience, it is best to seek care sooner than later, before the injury worsens. Any activity that you are not accustomed to doing will require a bit of training. It may seem strange, but after a long period of inactivity, you will need a bit of time to adjust to even walking longer distances. The pandemic has likely left many of us myself included a bit less active and it will take some training to get back to our previous fitness levels.
In answer to the question of what is a healthy amount of exercise, I think it is safe to say some physical activity daily is ideal. The type and intensity of the activity is a different story. For health and longevity purposes, a mix of aerobic exercise, strength training and energy cultivating exercise like yoga or tai chi is ideal for optimal health and wellness.