Did you know DNA influences your ability to burn fat for energy?
The future of exercise: PPARD, endurance and the “exercise pill”
You are stopped at a red light on your way to work, when a group of runners pass in front of you. They remind you of a time when you had the time and the energy for a workout. That was before the kids and the high-pressure job. You are well aware of the benefits of exercise – for your body and your mind, yet finding time for a workout is nearly impossible. You think, there must be a way to get the benefits of exercise without having to sacrifice time with your kids or what little sleep you get. Something that will tide you over until you find the time to be active once again. According to a new study there just might be a way in the near future for scientists to discover a drug that might prepare you for a marathon without ever having to leave the house. This “exercise-in-a-pill” acts through a gene named PPARD. It affects how our muscles burn energy to mimic the benefits of exercise.
We know that keeping fit requires regular training, because building your endurance largely involves gaining the right kind of skeletal muscles and properly managing our energy stores. There are two different types of skeletal muscle: sprinters have bulky “fast-twitch” muscle fibres that give them powerful bursts of energy for a short period of time, and endurance athletes have “slow-twitch” fibres that are resistant to fatigue. Fast-twitch muscles power themselves with sugars and burnout in a matter of minutes, whereas slow-twitch muscles prefer to burn fat and can keep going for hours.
Elite endurance athletes have muscles riddled with slow-twitch fibres, which is exactly what you need to run a marathon, and not so surprisingly you can increase them by training. Endurance training also prompts our slow-twitch muscles to shift from burning sugars to fats. Burning fat has a number of advantages. First, fat breakdown produces twice as much energy as sugar. Also, important organs like the brain rely completely on sugar and when your muscles burn fat it preserves the sugars for the brain.
At the centre of all these energy choices is the PPARD gene. It gives instructions to make a protein that controls the activity of many other genes, particularly the ones involved in fat breakdown. A variation of the PPARD gene known as rs2016520 results in increased production of the PPARD protein and an advantage for endurance activities. The rs2016520 variant is more common amongst endurance-athletes and is deemed one of the ten ‘endurance alleles’ linked to elite endurance athlete status.
When scientists first uncovered that turning on PPARD could mimic the benefits of exercise without actually having to exercise, they were pleasantly surprised. Given how complex human physiology is, finding a single gene that can affect so many different physiological changes (endurance, more slow-twitch muscle, elevated fat breakdown and resistance to weight gain) was quite rare. This uniqueness also makes PPARD an excellent future candidate for an “exercise pill”, because turning it on with a drug will be just as good as exercise. Such a “pill” will have huge therapeutic potential for people that can’t exercise, like the elderly, and chances are that it will probably also be misused as a performance enhancer. But for the average Joe or Jill, it just might be the encouragement we need when we are truly overwhelmed, to cut ourselves some slack without having to worry about harming our health.