There is literally no limitations on workouts when you are older. If you want to do it or if a certain fitness program is going to get you to achieve your goal whatever that may be, then just do it. I am 48 years old(young) and I do HIIT about four times per week along with running and lifting weight twice per week. Have my workouts changed from when I was 20? Yes. But only with time. I used to workout for three hours every day when I was in my 20s. I can’t do that anymore because I have a family and responsibilities, not because I’m unable to do it physically. The only difference you may find is you need a bit more recovery time after a hardcore workout. But usually this comes down to good nutrition, not age. Because we tend to be busier when we’re older we might neglect certain nutrition needs that will help in recovery and growth and also fat loss.