Be active daily for mental health
Prolonged periods of inactivity are often the cause of anger, frustration, lethargy and depression. On the other hand, those who are active regularly experience a better mood, feel more energetic, and overall enjoy a better life.
Be active daily for physical health
Being active does not necessarily mean doing a 25km run daily, and nor does it necessarily mean squatting double your bodyweight daily. Even lighter activities like walking, swimming, yoga, playing with kids, cleaning up the house, riding a bicycle, etc are all examples of being active. For most people, intense activities like weight training, sprinting, etc should ideally be kept to about 3-5 times a week, and on the other days, lighter activity is recommended.
Strength train and lift heavy
Almost every month there seems to some study that comes out with the finding that strength training, including lifting heavy weights has multiple health benefits. Starting from weight management, increased energy levels, better glucose metabolism, etc there are many reasons why you must strength train. You can strength train by using your own bodyweight and lifting barbells, dumbbell, kettlebell, etc.
Now cardio does not necessarily mean doing painfully long and slow activities like distance jogging. It can also be done in a short time with intense activities like sprinting, circuit training, kickboxing, etc. Infact, the intense options seem to provide better results overall, in terms of cardio fitness, improving body composition, increasing growth hormone production, etc.
Maintain healthy bodyweight and bodyfat levels
The extra fat increases your chances of getting a heart attack, diabetes, hypertension, etc. Also, I would like to mention that extra bodyweight, even in the form of muscle is not necessarily healthy in the long run. Whether muscle or fat, the extra weight has to be carried around by your joints, and at a later age, that can really start telling on your joint health.