David R. Meldrum, MD
Sports
Developing lifelong interests in physical activities is the best recommendation I could make to anyone wanting to stay healthy. Those who are very active will tell you that it simply makes you feel good and it becomes hard to imagine being sedentary. Being very active also helps to keep your bones and joints strong. By having more lean muscle mass you will be more sensitive to insulin and less likely to develop diabetes or hypertension later in life. A recent UCLA study showed that increasing lean muscle mass as little as 10% significantly lowered blood sugar and the incidence of diabetes. And, as pointed out under “Lifestyle and fertility”, both fertility and erectile function are also improved by being physically active.
Golf
Hiking
Trekking is a great sport to combine with travel and photography. This was one of our most spectacular hikes in Norway with Dr. Joe Gambone and his wife, Marge.
Skiing
Any skier will tell you that there isn’t any sport that gives the same sort of exhilarating exhaustion as a day on the slopes without long lift lines. When the snow is great there just isn’t anything to match it.
White water rafting
Our “oldest" son. Erik, is a white water rafting guide on weekends. I wouldn’t have gone on “Cherry Creek” without him in the boat. The name is meant to be funny- it’s really the upper Tuolumne where the creek enters. It’s rated as a 5 and is really 5.5 and almost unrunnable. It’s reputed to be the most difficult in the country. We had to take a fitness test and tough swim across the river to be allowed to go. On a river like this you really do have to "paddle or die", a favorite rafting tee shirt saying. You cannot go over rapids like these without paddling like mad because the boat's nose will fall more vertically, resulting in a dangerous swim.
Water sports
For many years, Claudia and I have enjoyed the Club Med and Sandals, largely because they have kayaking, scuba, water skiing, sailing and windsurfing at a lot of their resorts. 
I’ve particularly enjoyed scuba because it fits with my passion for photography and travel. For many years Claudia stayed on the beach but the first time I was asked to speak in Cairo she finally decided to take the plunge because the Red Sea is one of the top dive sites in the world and above the water it’s pretty bleak. Here is Claudia is feeding a sting ray in Grand Cayman. More of my favorite dive photos are below.
This lion fish was from the Red Sea.
This Manta was in Micronesia off Yap. They are most often in murky water because they feed off plankton.
These Morays were from the Red Sea. It's the only time I've seen these pale grey critters and the only time I've seen two together.
This soft coral in the red sea illustrates the vibrant colors that divers experience. One has to be very careful to control buoyancy so as to never touch the coral.
This Moray eel was also in the red sea. Those tiny fish dart around the eel's mouth cleaning his (or her) teeth. These Morays have very sharp teeth and don't let go, so approach with caution. I've only once had one come out after me and I just kept my camera between him and me.
Clown fish hide in the sea anemone, because their skin is coated to prevent the anemone from stinging it.
Finally, my best picture, of a puffer at night. Night diving is a bit spooky. Claudia was holding my arm very tightly while I took this picture!
Rollerblading and biking
The beach cities are a great place for activities, but we particularly enjoy the bike path that goes from south Redondo to north Manhattan Beach. We often stop in north Manhattan and walk up to Pancho’s Mexican restaurant on Highland, partly because of their great ceviche (marinated sea food) but also because we met in a disco across the street that was called Cisco’s at that time (we both like to dance). If you go to Pancho’s, look for the old painting of a beautiful Spanish senorita on the way down to the lower level. It was purchased by my father when they visited us in Madrid, where I was doing research for six months. When my parents died, we thought that would be a fitting home for it, so we sold it to the owner. If you see us sailing along the bike path, please stop us and say hello!
Weight training
The average person will gain about 30 pounds as they age and that is due to loss of lean muscle mass. 
Muscle tissue burns more calories because it is more metabolically active. Weight training for 30-60 minutes twice weekly will completely prevent that from occurring and the extra muscle will decrease the incidence of diabetes and hypertension. We both follow this habit and weigh the same as we did in our 20’s. So, don’t think of it as something only muscle-bound weight-lifters do- it’s simply a good long-term health habit.
Walking/running
You don’t have to be into sports to be active. A brisk walk or a run for 30 minutes most days of the week is the current recommendation for health and as I pointed out in the section on Lifestyle and Fertility, that turns out to be an amount of activity that increases both male and female fertility. We don’t play a sport every day but we do always take a brisk walk on any day we’re not enjoying another activity. It’s a great opportunity to discuss what went on in each others’ lives that day.
Turn off the TV!
The biggest enemy of health and fitness is the boob tube. It’s hard to believe, but the average American watches an average of more than four hours a day. We had no TV for three years while living in an apartment looking for the condo where we now live, and we didn’t miss it. Try just taping a favorite program to watch each night. You can then have time to get more sleep, more exercise, to read a book, and to cook a healthy meal. Let’s turn back the clock on all of the poor health habits that have led us to have the most expensive health system in the world with health statistics that lag behind most other developed countries.