Week 2
Last week, we looked at what movement does to our bodies at the deepest layer: the molecular level. While no one has yet to crack any one particular code, we can be certain that movement of almost any kind has an incredible and direct impact on the body.
Even if it is only 10 minutes, even if it is only a couple of reps. Movement mobilizes various cells in the body, switching on all sorts of biological pathways that need activating.
This week, we’re taking a different but similar look into how movement can affect the body. Below, find some of the latest research in the study of exercise-omics.
The Latest on Lactate
Did you know that 708 plasma metabolites change in response to resistance exercise? At the top of the list is lactate.
After being generated in muscle tissue, lactate has been shown by Dr. George Brooks’ lab (and others) to travel to other tissues like the brain, where it is burned and used preferentially over other available energy sources.
It also acts as a signaling molecule that induces brain-derived neurotrophic factor (BDNF). BDNF increases the growth of new neurons (neurogenesis) in the brain and improves learning and memory. Some animal studies suggest that lactate mediates the positive effect of exercise on learning and memory.
Lactate is a byproduct of glycolysis (the breakdown of sugar); it is an essential fuel that heart, liver, and brain cells depend on. When produced during exercise (especially high intensity workouts like cycling or sprinting, which shifts metabolism toward glycolysis to more quickly meet the high energetic demands), lactate switches on more than 600 genes involved in muscle adaptation, stimulates mitochondrial biogenesis (the process of making new mitochondria), and promotes protein synthesis, essential for muscle growth.
These incredibly diverse signaling pathways are stimulated when a person actively uses their muscles during exercise.
Movement and Brain Activity
Among the seemingly countless physiological changes that occur during exercise, one of the most profound is BDNF, or, brain-derived neurotrophic factor.
BDNF delays brain aging and neurodegenerative diseases; it also improves mental health disorders, like depression and anxiety. It does all of this by increasing neurogenesis and by boosting neuroplasticity. Neurogenesis—the process of forming new neurons—is important for learning, memory, and staving off brain atrophy. Neuroplasticity is the brain's capacity to reorganize itself in response to changes in its environment, making you more resilient. This is vital for how we handle daily stress or stress from a traumatic event. BDNF is an essential component to survival.
Unfortunately, BDNF production decreases as we age. But lifestyle can counter some of the effects of aging. BDNF is produced primarily in the brain, but it's made in other places, including the muscles, which is where the magic of movement comes into play.
A study from 2013 demonstrated that either vigorous or moderate exercise for 40 minutes increased BDNF more than vigorous or moderate exercise for 20 minutes. Overall, exercise caused an average 32% increase in BDNF levels compared to baseline levels.
In another study, mice that engaged in exercise were able to much more quickly maneuver a maze than those that were sedentary and did not exercise. Mice that had the best recall and were fastest at navigating the maze also had the highest levels of BDNF in their cells. At one point, the researchers blocked BDNF receptors in the mice that had participated in exercise. All initial mental strength and recall was obliterated; they had the same navigation capacities as the sedentary mice.
The evidence leans heavily not just on BDNF’s substantial impact on mental capabilities, but on the role exercise plays in activating BDNF.
Fountain of Youth
Many think of exercise as one of the best longevity elixirs. A new study has confirmed that to be true.
The research shows that humans produce a longevity and performance-enhancing hormone called MOTS-c that abounds after exercise. It’s uniquely encoded in the smaller mitochondrial genome (mtDNA) rather than the larger, nuclear genome (DNA).
That mtDNA is important: “[Mitochondria] coordinate and fine-tune metabolism by actively communicating to the rest of the body,” explained Changhan David Lee, one of the authors of the study. When working in tandem with mitochondria, MOTS-c is believed to regulate metabolic function throughout the body, as well as promote and increase healthy lifespan.
Humans express this powerful hormone during exercise. In fact, MOTS-c production increases 12-fold in the muscle in humans during exercise and remains elevated for up to four hours. It also increases by 50% in plasma during exercise, but levels return to baseline upon exercise completion. When the hormone was injected into old mice, it dramatically improved the aging mice’s physical capacity and performance, as well as extended healthy lifespan.
Barring injections of MOTS-c, these findings suggest that movement can present all sorts of metabolic possibilities for addressing age-related, physical decline.
That’s pretty good motivation to get after that sweat!
