We've been plagued by poor-quality studies making all the wrong conclusions! Of course, our metabolism drops and gets more and more defunct with each year of life passing as BMR depends on lean mass and sarcopenia is a scientific fact! Also, the higher your metabolic rate is, the faster you're aging! I think scientists keep forgetting about the Hayflick limit! Unlike cancer cells, our cells do not divine without a limit! The faster your metabolism is, the faster you will reach this limit! If you care about longevity, you need to aim to lower your BMR, not increase it. If you look at studies, it's not the athletes who live the longest, it's the scientists with a sedentary lifestyle who spend most of their day thinking, not running on the treadmill! I highly recommend to you The Longevity Book, which is based on the longest-ever study still going on at UC Riverside! I "feel great" is highly subjective. Brainless exercise also means upregulating growth factors, which also increase your risk of getting cancers. Exercise is also the single biggest source of ROS! Keep your cell turnover low, don't think autophagy comes at no cost. Keep your mitochondria healthy, and prevent senescence. Reduce exposure to environmental toxins, breathe clean air, drink pristine water, and eat less than what would make you full - all clean and simple foods! Walk 30 minutes a day - and that's all you need. Gyms and sports are industries often associated with injuries, a waste of productive time, and money. Be a turtle, not a hummingbird! Yeah, turtles are ugly, but live much, much longer that hummingbirds to enjoy the outside, not inner, beauty of this one-of-a-kind world!