Imagine your heart, 20 years younger. Sounds like science fiction, right? But that’s exactly what happened in a groundbreaking study on exercise and aging. As we age, our hearts undergo changes – they shrink, stiffen, and lose function. This increases our risk of cardiovascular disease and decreases our ability to exercise. But what if you could reverse these changes?
Researchers at UT Southwest in Dallas studied 50-year-old sedentary adults who didn’t have type 2 diabetes or cardiovascular disease. The participants were placed on one of two exercise protocols: a control group that did light stretching and bodyweight exercises, and a high-intensity exercise group. The high-intensity group did the same light exercises as the control group but also added vigorous workouts to their routine. This included 4-5 hours of training per week, with a significant portion at maximum steady-state intensity (think 75-80% max heart rate for 20-30 minutes) and a session of high-intensity interval training (HIIT) per week.
After two years, the high-intensity group’s hearts had structurally changed to resemble those of 30-year-olds. Their hearts were larger and more flexible. Essentially, the high-intensity exercise protocol had reversed 20 years of aging in their hearts.
But the benefits of high-intensity exercise don’t stop at the heart. Blood pressure decreases with regular vigorous exercise are comparable to those seen with antihypertensive medications. High blood pressure is a major risk factor for cardiovascular disease and has recently been established as one of the most important early risk factors for dementia and Alzheimer’s disease. So, the fact that exercise can improve blood pressure as well as drugs is incredibly encouraging.
Now, let’s talk about the brain benefits of getting your heart rate up high. When you push your muscles to work so hard that they can’t get oxygen fast enough, they adapt by using glucose for energy without the mitochondria. This process, called anaerobic metabolism, produces lactate as a byproduct. Lactate was once thought to be a waste product, but it’s actually a very energy-efficient fuel source that’s used by the muscles, brain, heart, and liver. It’s easier to make energy from lactate than glucose.
Lactate also acts as a signaling molecule. When you exercise, your muscles communicate with the rest of your body through lactate. This triggers adaptations like increased muscle size and cardiovascular improvements. The brain, which works hard during exercise, also responds to lactate. One of the key ways it responds is by increasing production of a molecule called brain-derived neurotrophic factor (BDNF). BDNF promotes the growth of new neurons in the hippocampus, a region of the brain important for learning and memory. It also supports neuroplasticity, the brain’s ability to adapt to a changing environment. People with depression have low levels of BDNF and neuroplasticity, which makes it hard for them to adapt and leads to depressive symptoms. So, high-intensity exercise is a great way to boost your brain health by increasing BDNF.
Lactate also signals the brain to make neurotransmitters like norepinephrine and serotonin. Studies have shown that even just 10 minutes of high-intensity interval training can improve cognition and mood by increasing these neurotransmitters. The protocols that maximize BDNF production involve high intensity and duration, such as 30-40 minutes at 80% max heart rate or 6 minutes of all-out HIIT intervals separated by recovery periods.
Finally, let’s talk about the anti-metastatic effects of vigorous exercise. We all know that exercise is one of the best ways to prevent cancer, but it also has benefits as an adjunct cancer treatment. One of the ways it does this is by killing circulating tumor cells through the shearing forces of increased blood flow. Circulating tumor cells escape the primary tumor, enter the bloodstream, and try to travel to other tissues and metastasize. But these cells are sensitive to the mechanical stress of blood flow and die when exposed to it. So, getting your blood flow up through exercise has an anti-metastatic effect.
In conclusion, high-intensity exercise has incredible benefits for both the heart and the brain. It can reverse 20 years of aging in the heart, improve blood pressure, boost brain health by increasing BDNF and neurotransmitters, reduce depression, and even have anti-metastatic effects. So, get out there and get your heart rate up – your body (and brain) will thank you!