When utilizing exercise to improve health, it's advisable to adhere to the Minimum Effective Dose-- a term coined by Nautilus fitness creator Arthur Jones and made popular by lifestyle hacker Tim Ferriss.
The idea is basically, to do enough so that you see improvement in the right areas without putting unnecessary stress on the joints or the body. In other words, you want the minimum effective dose in order to obtain the maximum benefit with the least unwanted side-effects.
There is a fair amount of evidence building to suggest that "Chronic cardio", or long cardiovascular workouts can contribute to Atrial Fribulations, or a disruption of the electrical activity of the heart.
HIIT or High Intensity Interval Training has been shown to have the benefits of steady-state cardio in a more compressed window of time. Take any cardio activity, I like hill sprints and bike sprints because of the low impact on joints in the leg, and do 6-10 sets of all out sprinting for 10-15 seconds, rest or go slowly for 30 seconds and repeat. You can get an extremely effective workout like this in 5 or 10 minutes. Just tag it on to the end of your current workout.
Anyone hanging around a gym long enough knows the older bodybuilders in the gym tend to have joint problems. This shows up after years of repetitions using heavy weights with no warmup and neglecting stretching/mobility work. If your goal is to be a 230lb IBBF Pro, then that might be necessary. However, for most people just trying to improve health, that type of training is counter-productive. I recommend, depending on current fitness level, working up to doing a 1 hour, fairly intense workouts 3 times per week.
Adding in long, slow walks and hikes 1-2 times per week is also a great idea. Research shows that "Blue Zones" or areas where the population reaches over 100 years of age at a higher than average rate tend to have communities centered around farming or low-level activity for long periods of time, among other things.