I have been a participant in aerobics on and off for about thirty five years and when I am at sea, I have devised a way to do a form of exercise while I am on watch.
First of all I made a playlist of my favourite music that has a good strong beat. Make sure it is at least the length of time you want to exercise; mine is 40 minutes long and I just play it on shuffle. Sometimes I only do 15 – 20 minutes, sometimes more. Whatever type of music you like, you can find fast-paced songs that will inspire you to move to the music.
Now you need to find a place that is safe for you to move around while underway. I choose to exercise behind the wheel. That way I can hang on to the binnacle and/or the radar arch supports, if it is rough, and I can also keep my eye on the instruments. All you need is a small space where you can lift your legs and move your arms.
I choose to do my aerobics on night watch. I use headphones attached to my iPad, which sits on a cockpit seat. I have so much fun, but I have to remember not to sing out loud as the Captain does not enjoy that. The other thing is that you have to be light on your feet. Stomping also is not appreciated. Two added benefits to doing it at night are, since there are only two of us onboard I am alone and can be as silly or as vigorous as I choose. And it is cooler at night, so I do not heat up as much as I would during the day.
Now that I am in my sixties, I have toned down the movements I use; the knee lifts are not as high as they used to be. The arm movements include active resistance to increase the energy needed. Sometimes I pump only one arm at a time, because I need to hold on with the other. For safety reasons when it is really rough I wear a harness and hook into our jacklines, which are on either side of the cockpit.
Other times I just dance in place, doing a version of the Twist, making sure my hips and torso get a good workout as well. I have great time flailing about while the boat races along, and it sure makes the night watches go faster.
I also lie on my back on the cockpit cushions and do abdominal exercises. It is not ideal, but I am sure the core strength you use just to stop rolling around is of great benefit. I use the slower songs to do squats, which are great for the upper thighs and the buttocks. If you are inclined to try aerobics on the water, do about five minutes of light movement and then do some stretching, after which you can go for it and make your heart rate increase. Make sure when you are done to stretch all the major muscle groups. This will help alleviate any stiffness, plus increase your range of movement, which is very important to maintain as we age.
I know that if I can just motivate myself to do this at least three times a week, if not everyday, my body will thank me. I will be able to go on that long hike when I make landfall and not be gasping for breath. There are lots of other things you can do to keep fit: yoga as well as using dynabands come to mind and I have even seen a stationary bike mounted in a sailboat. Then there are always the winches to grind when making sail adjustments. A fellow Bluewater cruiser told me he used to do step ups from the cockpit floor to the seat to get his blood moving.
Ocean passages do not need to be passive. Hopefully you can figure out some way to maintain your fitness levels and have some fun as well. Aerobics at sea, indeed!