Natalie’s response is great. Physician clearance and no current medical limitations are most important.
Just a couple of thoughts: 1) If you’re not currently doing intervals (speed up/slow down) on the treadmill I recommend them. Increase the intensity by either increasing speed and/or elevation) to the point where you begin to “lose your breath—hyperventilate. then slow down substantially for at least 2-3 minutes until you could maintain the pace for quite some time. Then increase intensity again. Repeat the intervals for the duration of your 30-40 minute workout. 2) With regard to your strength training, choose a resistance that challenges the target muscle(s) to the point where you can’t complete more than 1 or 2 more repetitions. The balance Natalie importantly suggests is simply, for example, that if you work a muscle group that causes flexion at a joint, be sure to work the muscle(s) that cause extension.
I agree that daily stretching is important. One thought, stretch following your treadmill or machine training. The target tissues will be “warm;” therefore, more responsive to the stretching exercises.
I add my congratulations to your commitment to fitness.