I exercise to maintain healthspan and keep fit, but I am by no means "fit" by the standards of people who are fit. I've seen what strong looks like (I'm not very big, at the oly gym I used to frequent I saw someone my height and weight bench > 3 plates at a meet), I've seen what performance endurance in a run, cycle, and swim looks like, and I've also seen what the vast majority of people at my office are like.<p>The author has some great reasons to grow and keep big muscles, but I have some thoughts to add for that "majority of people at the office" crowd.<p>Thought #1: there is one item that the author mentions that I think is absolutely critical yet buried all the way at the bottom.<p>> If you’re over 30 (or even in your 20s and able to afford it), hire a personal trainer to start. They can check your form and avoid any kind of injuries. With weights, it is really easy to get a bad form, no matter how many youtube videos you watch. I went to see a Physiotherapist 4 years after I started squats, and this is the best thing I’ve ever done. She retaught me everything I think I knew about squatting.<p>I cannot over-emphasise how important it is to focus on form so you avoid injuries. When you're older, hurting yourself will knock you off the exercise horse for years. Also, note that if you're in your 30s and have been mostly sedentary your adult life, the squat and deadlift may not even be movements that you have the range of motion to do.<p>Don't fall into the trap of pushing yourself because the program said so or the internet said so or because you feel inadequate next to the huge gains that people are showing off on the internet. There is absolutely no shame in taking things slower. Remember your goal is not to look good naked on the beach next summer, it is to maintain healthspan into your 70s.<p>Thought #2: cardio is important, the author's warning about "too much cardio because your joints will give out and you will lose muscle" is really odd and feels like I'm browsing /r/fitness in 2010. If you're very concerned about your joints, do something lower impact, like swim or cycle or row or the elliptical.<p>But do take your rest days.<p>Thought #3: stronglifts 5x5 is great if you're in your 20s or your early 30s. If you're older than that, well, you can still do it but please be careful. See thought #1 above.