The amount of calories that a person burns off per each hour of hiking depends on the persons weight.
But for example if you weigh 160 Lbs you should burn off between 430 and 440 calories during an hour hike and if you weigh 200 lbs or more you would burn off around 500 to 550 calories per hour of hiking.
Hiking is a good exercise to lose weight and to help improve your overall health and strengthen your heart and lungs.
Going for a hike is also a nice relaxing vacation and can help improve your mental health as well.
I lost 100 lbs of weight over 2 years of hiking a few times per month and I went on long hikes when I did go hiking.
It's a wonderful thing to do and hiking gets you outdoors, builds leg muscles, keeps you active and can help you live a longer healthier life as well.
So when you get old you should go hiking no matter what as long as you can continue to stand and walk as it will keep you moving and fit.