Josh reveals new science about exercise: how high-intensity interval training changes gene expression patterns and DNA methylation patterns, and influences telomere dynamics as well. Josh also reveals some shocking facts about how sedentary activity causes epigenetic changes within our genes.
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About Josh Denem, PhD
Josh is an ESSA Accredited Exercise Physiologist at the University of Ballarat. His research involves quantifying telomere dynamics, DNA methylation and gene expression changes induced after acute and chronic exercise training.
— Mike Mutzel MSc (@MikeMutzel) January 25, 2015
Research Gate: www.researchgate.net/profile/Joshua_Denham
02:50 Josh’s DNA/Exercise Journey: When Josh entered his PhD program, he began working on how exercise can alter the shape or structural changes of our genes. He began by looking at telomeres, the ends of your chromosomes. When exploring the impact of endurance exercise, such as ultra-marathon, they found that ultra-marathon runners had significantly longer white blood cell telomeres compared to healthy controls. This may reflect in a lower risk of chronic disease. They moved on to epigenetics and DNA methylation. Most of his research has been on DNA methylation mainly in leukocytes.
04:13 Telomeres: Telomeres cap the ends of your chromosomes, a repetitive stretch of DNA sequence. They do not make any RNA or protein. They are important in that they cap the ends of our protein coating genes. They prevent DNA degradation and chromosomal end-to-end fusion. They are a well-established marker of biological age and disease risk. As you age, telomeres become progressively shorter, until the cell becomes useless and undergoes programmed cell death. Leukocyte telomere length is shorter in patients with chronic diseases, such as cardio vascular disease, diabetes and cancer.
06:18 Exercise Recommendations for Cellular Health: Research shows that prolonged sitting is detrimental to your health. Any form of exercise or activity is helpful. Moderate intensity exercise is important for preventing disease and some cancers. You don’t have to do ultra-marathon or endurance exercise to receive the benefits. High intensity interval training (HIIT), short bouts of intense exercise repeated 3 to 8 times broken by rest periods of around 4 minutes, may be as effective, if not more effective, at improving established health parameters such as lipids, and blood pressure, than endurance exercise.
09:13 Epigenetics: Your DNA is transcribed into RNA. RNA is translated into proteins. DNA is the blueprint and the protein is the building blocks of your body, making all of your tissues. It is rare for the DNA sequence or alphabet to change. Epigenetics is a change in gene activity, independent to the change in DNA sequence. At any given time, our 21,000 genes will be up or down regulated, depending upon epigenetic regulation. Epigenetic modification include DNA methylation and histone modifications, such as acetylation. These are the main modifications that have been studied in conjunction with exercise.
11:25 Histones: A long strand of DNA needs to feed into small cells. How it fits is by wrapping around the nucleosome, which is 4 histone proteins.
12:58 Exercise, DNA and Your Brain: Josh has been studying leukocytes. They recruited healthy young males, take blood samples before and after 4 weeks, 3 times a week, of HIIT. There were a great many DNA methylation changes throughout the genome. The changes were in genes related to cancer. Many of these genes became methylated, possibly decreasing the risk of cancer. Also methylated were genes related to cardiovascular disease. DNA methylation changes occurred in micro-RNA genes. The micro-RNA gene went on to effect the mature RNA, which may then go on to affect gene activity.
15:05 Skeletal Muscle: If you exercise acutely, it dramatically de-methylates your skeletal muscle genome. A comparison of people who exercise at moderate intensity and those who did HIIT, found that those who did the acute exercise had the greatest reduction in DNA methylation in genes important for metabolism, including PGC-1 alpha.
17:20 Micro-RNA: Micro-RNA affect the translation from RNA to protein by binding to the mRNA and degrading it or regulating the translation that slows it down.
19:06 BDNF Changes: There are DNA methylation changes with acute and long term exercise. Some changes have been associated with improved stress coping mechanisms.
19:56 Cardiac Muscle Changes: There are particular maker RNAs related to training adaptations from aerobic exercise in the heart. They are differentially regulated after long term exercise and are associated with reduced blood pressure. There has been some research linking micro-RNA to regulation of blood pressure in context with aerobic exercise.
20:45 Adipose Tissue and Exercise: After 6 months of training in moderate intensity exercise, research found that adipose tissue and muscle samples before and after showed genome wide methylation changes. Some of the genes that had differential DNA methylation after the intervention were associated with adipocytes from adipose tissue associated with obesity.
23:02 Inactivity and Your Genome: After 9 days of bed rest, study participants had DNA methylation changes in their muscle. There was heavy DNA methylation after the bed rest. These genes were the same ones that were de-methylated after exercise. After 9 days of bed rest, study participants exercised, but could not get their methylation levels to what they were prior to the bed rest. If you are physically active, and then need to be on bed rest, it could be deleterious to your health. Keep moving.
25:49 Resistance Training and Epigenetics: There has been little to no research on epigenetics and resistance training. It probably does impact epigenetics. Aerobic has more impact upon gene expression and micro-RNA, particularly in leukocytes.
26:47 Josh’s Exercise: He does some aerobic exercise in the forms of long runs, but mixes it up with high intensity interval training and weights. Do what you can, when you can and mix it up.
27:27 Your Epigenetics and Your Children/Grand Children: What you do now, may influence the epigenetics of your offspring. Some DNA methylation markers are passed on. There are DNA methylation changes in utero. What a pregnant woman does during pregnancy may significantly impact her child’s methylation.
28:39 Paternal Epigenetic Influence: Paternal nutrition, toxin levels and activity level is important. Be active throughout your life and watch what you eat. When rats in a study were treated with pesticides, plastics and environmental toxins, the rat’s sperm DNA methylation was altered and passed on to offspring. This altered the characteristics of the offspring. They became obese, had reproductive problems and had poor overall health.
31:45 Josh’s View of the Future of Epigenetics: There will probably be epigenetic medicines. There are differential DNA methylation profiles in patients with particular diseases. We have over 150 epigenomes. Each cell type has a different epigenetic profile.
33:31 Josh’s Research: They are going to compare the telomeres of endurance trained athletes to healthy group and examine the molecular mechanisms for the longer telomere phenotypes. We know that endurance exercise is correlated with endurance exercise, but we don’t know why. They will also be examining other tissues for DNA methylation in endurance athletes.