Since my childhood, I was a bit chubby and worked really hard to come in a perfect shape😉.
The best thing which helped me is brisk walking. But was never satisfied and started running, Inspite being Asthamatic.I presumed that exercise means perspire, exhert and to get tired or exhaust.
Yoga changed my perception of fitness. Fitness is not too much of physical exhertion. Pranayam and yoga with proper knowledge of inhalation, hold and exhalation of breath can give much better result without force or strain.
Specially, in 40's running or gymming may cause more harm then to help, resulting in problems related to back or knee.
So, it is not essential for achieving anything only way is to hard work, *But smart work can get better results with minimum strain.*
Many a times investor also over work on their Investments. Planning for retirement and checking portfolio daily or weekly doesn't result in anything more then to damage it. *Investment also requires right mix of inhalation (accumulation), hold(gestation) and exhalation (distribution) to have healthy financial life.*
So, try not to exhert and smartly achieve desired goals.