Exercise and Longevity

There’s a couple of recent studies out that look at the effects of exercise using telomere length as a surrogate for longevity. Our telomeres shorten as we age.

The first study is (Beate Ø Osthus, Ida & Sgura, Antonella & Berardinelli, Francesco & Alsnes, Ingvild & Brønstad, Eivind & Rehn, Tommy & Kristian Støbakk, Per & Hatle, Håvard & Wisløff, Ulrik & Nauman, Javaid. (2012). Telomere Length and Long-Term Endurance Exercise: Does Exercise Training Affect Biological Age? A Pilot Study. PloS one. 7. e52769. 10.1371/journal.pone.0052769). The study:

Older endurance trained athletes had longer telomere length compared with older people with medium activity levels (T/S ratio 1.12±0.1 vs. 0.92±0.2, p = 0.04). Telomere length of young endurance trained athletes was not different than young non-athletes (1.47±0.2 vs. 1.33±0.1, p = 0.12).

A second study looked at the effects of the specific mode of exercise (Christian M Werner, Anne Hecksteden, Arne Morsch, Joachim Zundler, Melissa Wegmann, Jürgen Kratzsch, Joachim Thiery, Mathias Hohl, Jörg Thomas Bittenbring, Frank Neumann, Michael Böhm, Tim Meyer, Ulrich Laufs; Differential effects of endurance, interval, and resistance training on telomerase activity and telomere length in a randomized, controlled study , European Heart Journal, ehy585).

The results were interesting.

This randomized, controlled, and prospective training study shows that specific training protocols lead to differential effects on cellular aging. Aerobic endurance and high-intensive interval training, but not resistance training, increases telomerase activity and telomere length in blood mononuclear cells.

This study was fairly impressively powered with 124 subjects.

One hundred and twenty-four healthy previously inactive individuals completed the 6 months study. Participants were randomized to three different interventions or the control condition (no change in lifestyle): aerobic endurance training (AET, continuous running), high-intensive IT (4 × 4 method), or RT (circle training on 8 devices), each intervention consisting of three 45 min training sessions per week.

The specific results were statistically significant.

Telomerase activity in blood mononuclear cells was up-regulated by two- to three-fold in both endurance exercise groups (AET, IT), but not with RT. In parallel, lymphocyte, granulocyte, and leucocyte TL increased in the endurance-trained groups but not in the RT group. Magnet-activated cell sorting with telomerase repeat-ampliflication protocol (MACS-TRAP) assays revealed that a single bout of endurance training—but not RT—acutely increased telomerase activity in CD14+ and in CD34+ leucocytes.

Things to note is that this is an older (~49 years on average), untrained group of people who were at healthy BMI (~24).


The mechanism is interesting.

Exercise Intensity and Blood Sugar

I’ve come to the conclusion that for me as a diabetic intense exercise (at high heart rates) is not good for my blood sugar control. Here’s a study of Type 1 Diabetics which shows the increase in blood sugar from intense exercise (Vinutha S, Paul F, Raymond D, et al. Effect of exercise intensity and blood glucose level on glucose requirements to maintain stable glycaemia during exercise in individuals with type 1 diabetes. Int J Pediatr Endocrinol. 2015;2015(Suppl 1):O39). The study looked at:

Nine young adults with T1D underwent euglycaemic clamps, whereby stable blood glucose levels between 4.5 to 6mmol/L were maintained during the study at basal insulin levels. Participants performed up to 40 minutes of exercise at four different exercise intensities (35%, 50%, 65% and 80% VO2peak) on four separate days following a randomised counterbalanced design. In a subsequent experiment, eight participants underwent either a euglycaemic or hyperglycaemic (9.5 – 10.5mmol/L) clamp at basal insulin levels, during which they performed 40 minutes of exercise at 50% VO2peak, on two separate days. In both studies, glucose infusion rates (GIR) to maintain stable glycaemia were measured during exercise, constant deuterated glucose was infused to determine glucose kinetics and blood samples were collected for the analysis of glucoregulatory hormones.

The result was:

The average GIR to maintain euglycaemia during exercise was 2.0±0.9, 4.0±1.5, and 4.1±1.7g/h (mean±SEM) at 35%, 50% and 65% VO2peak, respectively. These GIRs were all significantly greater than that at 80% VO2peak where no glucose was required (p<0.05). Exercise at 80% VO2peak was associated with a significant rise in catecholamine levels and endogenous glucose production (p<0.05). The average GIR to maintain stable glycaemia during exercise performed during the second experiment at 50% VO2peak was similar at euglycaemia (4.9±2.1g/h) and hyperglycaemia (5.5±2.5g/h; p>0.05).


Fasted Workouts and 24 Hour Fat Oxidation

Fasted workouts cause increased 24 hour fat oxidation (Iwayama K, Kurihara R, Nabekura Y, et al. Exercise Increases 24-h Fat Oxidation Only When It Is Performed Before Breakfast. EBioMedicine. 2015;2(12):2003-2009).

Under energy-balanced conditions, 24-h fat oxidation was increased by exercise only when performed before breakfast. Transient carbohydrate deficits, i.e., glycogen depletion, observed after morning exercise may have contributed to increased 24-h fat oxidation.

These results probably don’t hold true for low carb athletes since our glycogen stores are probably already somewhat depleted.

Energy Expenditure in Hunter Gatherers

We are told that our western lifetyle is to blame and that all we need to eat less and move more. And that sounds intuitively true. The move more part was challenged by a study of the Hadza people (Pontzer H, Raichlen DA, Wood BM, Mabulla AZP, Racette SB, et al. (2012) Hunter-Gatherer Energetics and Human Obesity. PLOS ONE 7(7): e40503.).

…average daily energy expenditure of traditional Hadza foragers was no different than that of Westerners after controlling for body size. The metabolic cost of walking (kcal kg−1 m−1) and resting (kcal kg−1 s−1) were also similar among Hadza and Western groups.

The similarity in metabolic rates across a broad range of cultures challenges current models of obesity suggesting that Western lifestyles lead to decreased energy expenditure.

We hypothesize that human daily energy expenditure may be an evolved physiological trait largely independent of cultural differences.

Interesting article (What a hunter-gatherer diet does to the body in just three days).

My other lasting impression was how little time they spent getting food. It appeared as though it took just a few hours a day — as simple as going round a large supermarket. Any direction you walked there was food — above, on and below ground.

MAF Training And Metabolic Syndrome

There’s an interesting study which looked at two months of training at FATmax to see what the effects on Metabolic Syndrome (Dumortier M, Brandou F, Perez-Martin A, Fedou C, Mercier J, Brun JF. Low intensity endurance exercise targeted for lipid oxidation improves body composition and insulin sensitivity in patients with the metabolic syndrome. Diabetes Metab. 2003 Nov;29(5):509-18). The study showed good improvements from MAF level of training intensity.

The patients exhibited a significant reduction in body weight (- 2.6 +/- 0.7 kg; P=0.002), fat mass (- 1.55 +/- 0.5 kg; P=0.009), waist (- 3.53 +/- 1.3 cm; P<0.05) and hip (- 2.21 +/- 0.9 cm; P<0.05) circumferences, and improved the ability to oxidize lipids at exercise (crossover point: + 31.7 +/- 5.8 W; P<0.0001; LIPOX(max): + 23.5 +/- 5.6 W; P<0.0001; lipid oxidation: + 68.5 +/- 15.4 mg.min(-1); P=0.0001). No clear improvement in either lipid parameters or fibrinogen were observed.

There were significant improvements in the markers of Metabolic Syndrome.

The surrogates of insulin sensitivity evidenced a decrease in insulin resistance: HOMA%S (software): + 72.93 +/- 32.64; p<0.05; HOMA-IR (simplified formula): – 2.42 +/- 1.07; P<0.05; QUICKI: + 0.02 +/- 0.004; P<0.01; SI=40/I: + 3.28 +/- 1.5; P<0.05. Significant correlations were found between changes in body weight and HOMA-IR and between changes in LIPOX(max) and QUICKI.

Here’s a longer term study which shows positive results over a longer time period (Drapier E (2018) Long term (3 years) weight loss after low intensity endurance training targeted at the level of maximal muscular lipid oxidation. Integr Obesity Diabetes 4).

Average weight loss was -2.95 ± 0.37 kg after 3 months, -4.56 ± 0.68 kg after 1 year, -5.31 ± 1.26 kg at 2 years and -8.49 ± 2.39 kg at 3 years.

The beauty of this study was that it compared low intensity exercise to a low fat diet.

This study shows that this low intensity exercise training maintains its weight-reducing effect 3 years while diet is no longer efficient, and that this effect is initially related to muscular ability to oxidize lipids but that metabolic and behavioral adaptations have been further developed and contribute to a long lasting effect.

The results are powerful.

Here’s a third related study (J. O. Holloszy and E. F. Coyle. Adaptations of skeletal muscle to endurance exercise and their metabolic consequences. Journal of Applied Physiology 1984 56:4, 831-838).

The major metabolic consequences of the adaptations of muscle to endurance exercise are a slower utilization of muscle glycogen and blood glucose, a greater reliance on fat oxidation, and less lactate production during exercise of a given intensity.

These adaptations play an important role in the large increase in the ability to perform prolonged strenuous exercise that occurs in response to endurance exercise training.

From the results:

…Probably the most important of these is an increase in mitochondria with an increase in respiratory capacity. One consequence of the adaptations induced in muscle by endurance exercise is that the same work rate requires a smaller percentage of the muscles’ maximum respiratory capacity and therefore results in less disturbance in homeostasis.

A second consequence is increased utilization of fat, with a proportional decrease in carbohydrate utilization, during submaximal exercise.


FASTER Study – Three Hour Magic Number

In previous posts I’ve taken a critical look at the FASTER study (FASTER Again – Checking a number on Ben Greenfield’s data). In particular, I took at look at Ben Greenfield’s three hour data (FASTER10 – Ben Greenfield – Three Hour VO2 testing). Ben looked like he still had gas left in his tank after three hours of sub-maximal running.

The Vegan

But what about Damian Stoy (FASTER Subject 43)? He’s a vegan who is not at all fat fueled. He never got more fuel from fat than 50% and that was at 45% of his VO2max.

At 64% of VO2max, Damian was getting nearly zero of his energy from fat. His carbohydrate oxidation rate was ~10 kcal/min. So, in three hours of running, Damian burned ~1800 kcals which has to be close to his entire glycogen stores.

My conclusion? Beyond this time and intensity being carb fueled isn’t a great choice. The reason that marathons are 26 miles is historical and practical. People just can’t run hard for longer times.


CrossFit Injury Rate Study

Interesting study of CrossFit injury rates (Hak PT, Hodzovic E, Hickey B. The nature and prevalence of injury during CrossFit training. J Strength Cond Res. 2013 Nov 22.). The study reported on an on-line survey so it was probably quite slanted in the results.

An online questionnaire was distributed amongst international CrossFit online forums. Data collected included general demographics, training programs, injury profiles and supplement use. A total of 132 responses were collected with 97 (73.5%) having sustained an injury during CrossFit training. A total of 186 injuries were reported with 9 (7.0%) requiring surgical intervention. An injury rate of 3.1 per 1000 hours trained was calculated.




Fat Burning – Running vs Cycling

In a previous post I took at look at the exercise intensity which produced the maximum fat oxidation rates (Maximal Fat Oxidation Rates in an Athletic Population). A study took a look at the fat oxidation rates which happen when exercise is performed at the FATmax rate with cycling and running.

There was a significant difference in the rate of fat oxidation between the two (Juul Achten, Michelle C Venables, Asker E Jeukendrup. Fat oxidation rates are higher during running compared with cycling over a wide range of intensities. Metabolism, Volume 52, Issue 6, June 2003, Pages 747-752.).

Maximal fat oxidation was 28% higher when walking [ed: did they mean running?] compared with cycling, but the intensity, which elicits maximal fat oxidation, is not different between these 2 exercise modes.

These are interesting results. Although both exercises were done at the same intensity level (as measured by heart rate) they resulted in different amounts of total fat oxidation.

This leads me to conclude that although cycling and running can be both done at the MAF heart rate they are not equal for fat oxidation rates.

What About Rowing?

It would be interesting to see what the fat oxidation rate at FATmax is for rowing (ROW) and other modes. Turns out there’s a study for that too. (Egan B, Ashley DT, Kennedy E, O’Connor PL, O’Gorman DJ. Higher rate of fat oxidation during rowing compared with cycling ergometer exercise across a range of exercise intensities. Scand J Med Sci Sports. 2016 Jun;26(6):630-7. The study found that:

…FATox is higher during ROW compared with CYC exercise across a range of exercise intensities matched for energy expenditure…

The details show:

Despite similar oxygen consumption, rates of fat oxidation (FATox ) were ∼45% higher during ROW compared with CYC (P < 0.05) across a range of power output increments.

The crossover point for substrate utilization occurred at a higher relative exercise intensity for ROW than CYC (57.8 ± 2.1 vs 42.1 ± 3.6%VO2peak , P < 0.05).

Putting the Pieces Together

  • Rowing is ~45% better than cycling.
  • Running is ~28% better than cycling.
  • Rowing should be ~17% better than running.

Mechanism to Explain Differences

The degree to which an exercise engages muscles determines the maximum fat oxidation. Rowing has more muscle involvement than running which has more muscle involvement than cycling.




FATmax Training Results

In principle, training at FATmax (Maximal Fat Oxidation Rates in an Athletic Population) should result in significant loss of body fat and the resulting improvement in body composition. However, it is something of a surprise just how few studies have been performed to determine the effectiveness of this type of training. A meta-analysis (A. J. Romain, et.al. Physical Activity Targeted at Maximal Lipid Oxidation: A Meta-Analysis. (J Nutr Metab. 2012; 2012: 285395.) took a look and only found 15 total studies of this subject which fit their criteria. These studies were relatively small but the results were encouraging.

This meta-analysis confirms the conclusions of the individual studies, that are very low intensity training targeted at the level of maximal fat oxidation significantly decreases body weight, fat mass, waist circumference and total cholesterol. On the average, the effects of this variety of training are thus well confirmed, and their average magnitude is more precisely described.

Study Limitations

Only 5 studies include a control (nonexercising) group. There were also no longer term studies.

Volume of Training

Interestingly, some studies demonstrated an important average weight loss (8 kg over two months) with a protocol based on 90 min/day exercise at the level of maximal lipid oxidation. This could suggest that large weekly volumes of exercise training may be much more efficient than those used usually (i.e, 3 × 45 min/week).

Loss of Visceral Fat

The study called out a reference paper (Ohkawara K, et.al. A dose-response relation between aerobic exercise and visceral fat reduction: systematic review of clinical trials. Int J Obes (Lond). 2007 Dec;31(12):1786-97. ) which indicated that there is a dose response between aerobic exercise and loss of visceral fat.

… at least 10 METs x h/w in aerobic exercise, such as brisk walking, light jogging or stationary ergometer usage, is required for visceral fat reduction, and that there is a dose-response relationship between aerobic exercise and visceral fat reduction in obese subjects without metabolic-related disorders.


Low Carb High Intensity Interval Training Performance

Here’s a new study that looked at the Low Carb diet and High Intensity Interval Training performance (Lukas Cipryan, Daniel J. Plews, Alessandro Ferretti, Phil B. Maffetone, and Paul B. Laursen. Effects of a 4-Week Very Low-Carbohydrate Diet on High-Intensity Interval Training Responses. J Sports Sci Med. 2018 Jun; 17(2): 259–268.).

The purpose of the study was to examine the effects of altering from habitual mixed Western-based (HD) to a very low-carbohydrate high-fat (VLCHF) diet over a 4-week timecourse on performance and physiological responses during high-intensity interval training (HIIT).

Eighteen moderately trained males (age 23.8 ± 2.1 years) consuming their HD (48 ± 13% carbohydrate, 17 ± 3% protein, 35 ± 9% fat) were assigned to 2 groups. One group was asked to remain on their HD, while the other was asked to switch to a non-standardized VLCHF diet (8 ± 3% carbohydrate, 29 ± 15% protein, 63 ± 13% fat) for 4 weeks.

Participants performed graded exercise tests (GXT) before and after the experiment, and an HIIT session (5x3min, work/rest 2:1, passive recovery, total time 34min) before, and after 2 and 4 weeks. Heart rate (HR), oxygen uptake (V̇O2), respiratory exchange ratio (RER), maximal fat oxidation rates (Fatmax) and blood lactate were measured. Total time to exhaustion (TTE) and maximal V̇O2 (V̇O2max) in the GXT increased in both groups, but between-group changes were trivial (ES ± 90% CI: -0.1 ± 0.3) and small (0.57 ± 0.5), respectively.

Between-group difference in Fatmax change (VLCHF: 0.8 ± 0.3 to 1.1 ± 0.2 g/min; HD: 0.7 ± 0.2 to 0.8 ± 0.2 g/min) was large (1.2±0.9), revealing greater increases in the VLCHF versus HD group. Between-group comparisons of mean changes in V̇O2 and HR during the HIIT sessions were trivial to small, whereas mean RER decreased more in the VLCHF group (-1.5 ± 0.1). Lactate changes between groups were unclear.

Adoption of a VLCHF diet over 4 weeks increased Fatmax and did not adversely affect TTE during the GXT or cardiorespiratory responses to HIIT compared with the HD.

I have a lot of respect for Phil Maffetone and Paul Larson. Both are long time advocates of Low Carb Athletics. Phil Maffetone coached Mark Allen to multiple wins at Kona Ironman (Mark Allen Interview: A look back at working with Phil Maffetone and what it means for today’s triathlete).