Acute modification in plasma lipid levels in ultramarathon runners

Acupoint Catgut Embedding Improves Lipid Metabolism in Exercise-Induced Fatigue Rats via the PPAR Signaling Pathway

To improve the phenomenon of exercise-induced fatigue that often occurs during horse racing, we previously studied the improvement in exercise tolerance by acupoint catgut embedding preconditioning in an exercise-induced fatigue rat model. We found that acupoint catgut embedding pretreatment effectively improved animal exercise tolerance. Here, by combining transcriptomics and metabolomics, we aimed to explore the underlying mechanisms of this improvement. We used blood biochemical detection combined with ELISA to detect triglyceride (TG), total cholesterol (TC), lactate dehydrogenase (LDH), high-density lipoprotein (HDL), alanine transaminase (ALT), aspartate aminotransferase (AST), and glucose (GLU), arachidonic acid (AA), and free fatty acid (FFA) content and found that acupoint embedding can correct FFA, AA, TG, LDH, and AST in the blood. We used RT-qPCR to measure the expression of genes in tissue from the quadriceps femoris muscle. We found that solute carrier family 27 member 2 (Slc27a2), fatty acid binding protein 1 (Fabp1), apolipoprotein C3 (Apoc3), and lipoprotein lipase (Lpl) genes in the peroxisome proliferator-activated receptor (PPAR) signaling pathway were important. The regulation of lipid metabolism through the PPAR signaling pathway was important for improving the exercise endurance of rats in our exercise-induced fatigue model. Therefore, we conclude that acupoint catgut embedding can not only promote body fat decomposition and reduce lactic acid accumulation but also promote the repair of tissue damage and liver damage caused by exercise fatigue. Acupoint catgut embedding regulates the PPAR signaling pathway by upregulating Lpl expression and downregulating Slc27a2, Fabp1, and Apoc3 expression to further improve body fat metabolism.

Physiological Changes, Activity, and Stress During a 100-km-24-h Walking-March

Background

Long-endurance exercises like ultramarathons are known to elicit various metabolic and physiological changes in the human body. However, little is known about very long-duration exercise at low intensities regarding healthy human subjects.

Aim

The purpose of this study was to evaluate changes in body composition and metabolism in long-endurance but low-intensity events.

Methods

Twenty-five male and 18 female healthy recreational athletes (age 34.6 ± 8.8 years; BMI: 22.4 ± 2.0 kg/m²) of the "100 km Mammutmarsch" were recruited for participation during the events in 2014-2016. Other than classical ultramarathons, the "Mammutmarsch" is a hiking event, in which participants were required to walk but not run or jog. It was expected to complete the 100-km distance within 24 h, resulting in a calculated mean speed of 4.17 km/h, which fits to the mean speed observed (4.12 ± 0.76 km/h). As not all participants reached the finish line, comparison of finishers (FIN, n = 11) and non-finishers (NON, n = 21) allowed differential assessment of performance. Body composition measured through bioelectrical impedance analysis (BIA) was determined pre- and post-event, and serum samples were taken pre-event, at 30, 70, and 100 km to determine NT-pro-BNP, troponin T, C-reactive protein (CRP), cortisol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglycerides, total cholesterol, total creatine kinase (CK), CK-MB, aminotransferase (AST), ALT, and sodium levels. Nineteen participants wore actimeter armbands (SenseWear^®) to gain information about body activity and exercise intensity [metabolic equivalent of task (MET)]. Sixteen participants wore mobile heart rate monitors to assess mean heart rate during the race. Serum parameter alterations over the course of the race were analyzed with mixed-effects ANOVA and additional t-tests. All serum parameters were analyzed for correlation concerning different MET levels, speed, age, BMI, baseline NT-pro-BNP, mean heart rate during the race, and sex with linear regression analysis.

Results

We found significant elevations for muscle and cardiac stress markers (CRP, CK, CK-MB, AST, ALT, cortisol, and NT-pro-BNP) as well as decreasing markers of lipid metabolism (cholesterol, triglycerides, LDL). Although the intensity level demanded from our participants was low compared with other studies on (ultra-) marathons, the alteration of tested parameters was similar to those of high-intensity exercise, e.g., NT-pro-BNP showed a fourfold increase (p < 0.01) and LDL decreased by 20% (p = 0.05). Besides the duration of exercise, age, BMI, training status, and sex are relevant parameters that influence the elevation of stress factors. Notably, our data indicate that NT-pro-BNP might be a marker for cardiovascular fitness also in healthy adults.

Conclusion

This low-intensity long-endurance walk evoked a strong systemic reaction and large cell stress and shifted to a favorable lipid profile, comparable to higher intensity events. Despite increasing cardiac stress parameters, there were no indications of cardiac cell damage. Remarkably, the duration seems to have a greater influence on stress markers and metabolism than intensity.

The Regulation of Fat Metabolism During Aerobic Exercise

Since the lipid profile is altered by physical activity, the study of lipid metabolism is a remarkable element in understanding if and how physical activity affects the health of both professional athletes and sedentary subjects. Although not fully defined, it has become clear that resistance exercise uses fat as an energy source. The fatty acid oxidation rate is the result of the following processes: (a) triglycerides lipolysis, most abundant in fat adipocytes and intramuscular triacylglycerol (IMTG) stores, (b) fatty acid transport from blood plasma to muscle sarcoplasm, (c) availability and hydrolysis rate of intramuscular triglycerides, and (d) transport of fatty acids through the mitochondrial membrane. In this review, we report some studies concerning the relationship between exercise and the aforementioned processes also in light of hormonal controls and molecular regulations within fat and skeletal muscle cells.

The effects of exercise training on lipid metabolism and coronary heart disease

Blood lipoproteins are formed by various amounts of cholesterol (C), triglycerides (TGs), phospholipids, and apolipoproteins (Apos). ApoA1 is the major structural protein of high-density lipoprotein (HDL), accounting for ~70% of HDL protein, and mediates many of the antiatherogenic functions of HDL. Conversely, ApoB is the predominant low-density lipoprotein (LDL) Apo and is an indicator of circulating LDL, associated with higher coronary heart disease (CHD) risk. Thus, the ratio of ApoB to ApoA1 (ApoB/ApoA1) is used as a surrogate marker of the risk of CHD related to lipoproteins. Elevated or abnormal levels of lipids and/or lipoproteins in the blood are a significant CHD risk factor, and several studies support the idea that aerobic exercise decreases CHD risk by partially lowering serum TG and LDL-cholesterol (LDL-C) levels and increasing HDL-C levels. Exercise also exerts an effect on HDL-C maturation and composition and on reverse C transport from peripheral cells to the liver to favor its catabolism and excretion. This process prevents atherosclerosis, and several studies showed that exercise training increases heart lipid metabolism and protects against cardiovascular disease. In these and other ways, it more and more appears that regular exercise, nutrition, and strategies to modulate lipid profile should be viewed as an integrated whole. The purpose of this review is to assess the effects of endurance training on the nontraditional lipid biomarkers, including ApoB, ApoA1, and ApoB/ApoA1, in CHD risk.

Effect of mountain ultra-marathon running on plasma angiopoietin-like protein 4 and lipid profile in healthy trained men

Purpose

Angiopoietin-like protein 4 (ANGPTL4) regulates lipid metabolism by inhibiting lipoprotein lipase activity and stimulating lipolysis in adipose tissue. The aim of this study was to find out whether the mountain ultra-marathon running influences plasma ANGPTL4 and whether it is related to plasma lipid changes.

Methods

Ten healthy men (age 31 ± 1.1 years) completed a 100-km ultra-marathon running. Plasma ANGPTL4, free fatty acids (FFA), triacylglycerols (TG), glycerol (Gly), total cholesterol (TC), low (LDL-C) and high (HDL-C) density lipoprotein-cholesterol were determined before, immediately after the run and after 90 min of recovery.

Results

Plasma ANGPTL4 increased during exercise from 68.0 ± 16.5 to 101.2 ± 18.1 ng/ml (p < 0.001). This was accompanied by significant increases in plasma FFA, Gly, HDL-C and decreases in plasma TG concentrations (p < 0.01). After 90 min of recovery, plasma ANGPTL4 and TG did not differ significantly from the exercise values, while plasma FFA, Gly, TC and HDL-C were significantly lower than immediately after the run.

TC/HDL-C and TG/HDL-C molar ratios were significantly reduced. The exercise-induced changes in plasma ANGPTL4 correlated positively with those of FFA (r = 0.73; p < 0.02), and HDL-C (r = 0.69; p < 0.05). Positive correlation was found also between plasma ANGPTL4 and FFA concentrations after 90 min of recovery (r = 0.77; p < 0.01).

Conclusions

The present data suggest that increase in plasma FFA during mountain ultra-marathon run may be involved in plasma ANGPTL4 release and that increase in ANGPTL4 secretion may be a compensatory mechanism against fatty acid-induced oxidative stress. Increase in plasma HDL-C observed immediately after the run may be due to the protective effect of ANGPTL4 on HDL.

Impact of angiotension I converting enzyme gene I/D polymorphism on running performance, lipid, and biochemical parameters in ultra-marathoners

The insertion (I) or deletion (D) polymorphism in the angiotension I converting enzyme gene, (ACE I/D, rs1799752) is associated with human exercise endurance and performance. However, most of the aforementioned studies focus on marathons, swimming, and triathlons, while the ACE polymorphism in ultra-marathoners has not yet been reported. We studied the impact of ACE I/D polymorphism in ultra-marathoners and investigated its relationship with lipid profiles, interleukin-6 (IL-6), and high-sensitivity C-reactive protein (hs-CRP) levels in runners before and after ultra-marathon racing.This observational study used data from a 100-km ultra-marathon in Taipei, Taiwan. Twenty-four male participants were analyzed for their ACE insertion/deletion polymorphism, lipid profiles, hs-CRP, IL-6 in serum immediately before and after ultra-marathon running.In our 24 subjects analyzed, 7, 14, and 3 subjects were of I/I, I/D, and D/D genotypes, respectively. Runners with the D polymorphism (I/D and D/D) showed a trend of better performance in the 100-km ultra-marathon (measured by completion time in minutes, P = .036). In this group, the previous best marathon performance was also significantly better than the I/I group (P = .047). After adjusting for body mass index (BMI), the difference in performance was not significant. Ketone levels, IL-6, and hs-CRP levels were highly increased at immediately and 24-hour post-race. No correlation was found between different ACE polymorphisms and common biochemical parameters examined.We report the first study in the impact of the ACE I/D (rs1799752) on ultra-marathoners. Presence of the D polymorphism in ACE gene is associated with better performance, although the BMI of the runners contribute as a major factor. There was no difference in the biochemical or lipid parameters measured among different ACE polymorphisms.

Physiology and Pathophysiology in Ultra-Marathon Running

In this overview, we summarize the findings of the literature with regards to physiology and pathophysiology of ultra-marathon running. The number of ultra-marathon races and the number of official finishers considerably increased in the last decades especially due to the increased number of female and age-group runners. A typical ultra-marathoner is male, married, well-educated, and ~45 years old. Female ultra-marathoners account for ~20% of the total number of finishers. Ultra-marathoners are older and have a larger weekly training volume, but run more slowly during training compared to marathoners. Previous experience (e.g., number of finishes in ultra-marathon races and personal best marathon time) is the most important predictor variable for a successful ultra-marathon performance followed by specific anthropometric (e.g., low body mass index, BMI, and low body fat) and training (e.g., high volume and running speed during training) characteristics. Women are slower than men, but the sex difference in performance decreased in recent years to ~10–20% depending upon the length of the ultra-marathon. The fastest ultra-marathon race times are generally achieved at the age of 35–45 years or older for both women and men, and the age of peak performance increases with increasing race distance or duration. An ultra-marathon leads to an energy deficit resulting in a reduction of both body fat and skeletal muscle mass. An ultra-marathon in combination with other risk factors, such as extreme weather conditions (either heat or cold) or the country where the race is held, can lead to exercise-associated hyponatremia. An ultra-marathon can also lead to changes in biomarkers indicating a pathological process in specific organs or organ systems such as skeletal muscles, heart, liver, kidney, immune and endocrine system. These changes are usually temporary, depending on intensity and duration of the performance, and usually normalize after the race. In longer ultra-marathons, ~50–60% of the participants experience musculoskeletal problems. The most common injuries in ultra-marathoners involve the lower limb, such as the ankle and the knee. An ultra-marathon can lead to an increase in creatine-kinase to values of 100,000–200,000 U/l depending upon the fitness level of the athlete and the length of the race. Furthermore, an ultra-marathon can lead to changes in the heart as shown by changes in cardiac biomarkers, electro- and echocardiography. Ultra-marathoners often suffer from digestive problems and gastrointestinal bleeding after an ultra-marathon is not uncommon. Liver enzymes can also considerably increase during an ultra-marathon. An ultra-marathon often leads to a temporary reduction in renal function. Ultra-marathoners often suffer from upper respiratory infections after an ultra-marathon. Considering the increased number of participants in ultra-marathons, the findings of the present review would have practical applications for a large number of sports scientists and sports medicine practitioners working in this field.

Impact of the 24-h ultramarathon race on homocysteine, oxidized low-density lipoprotein, and paraoxonase 1 levels in professional runners

The impact of the 24-h ultramarathon race on homocysteine (Hcy) and oxidized low-density lipoprotein (oxLDL) levels, two well-recognized cardiovascular risk factors, has not been deeply investigated. Similarly, no information exists on paraoxonase 1 (PON1), an antioxidant enzyme associated with high-density lipoproteins, which may detoxify oxLDL and Hcy-thiolactone, hence preventing their proatherogenic action. Taking this into account, a competitive 24-h ultramarathon race was organized in Reggio-Emilia (Italy) recruiting professional runners (n = 14) from the Italian Ultramarathon and Trail Association. Blood samples were collected from each participant before, during (14 h), and immediately after (24 h) the competition, thus to monitor the serum changes in Hcy, oxLDL, and PON1 levels, as well as other oxidative stress-related parameters, namely reactive oxygen metabolites (ROM) and total antioxidant capacity (PAT). As a result, a significant PON1 increase was recorded after 14 h of racing that persisted until the end of the performance. The same trend was observed for PAT values, which positively correlated to PON1 levels (R = 0.643, P<0.001). Hcy, oxLDL, and ROM remained almost unchanged throughout the competition. In conclusion, the present study suggested a protective role of PON1 in sustaining the antioxidant defense system and contrasting lipoprotein oxidative modifications over the 24-h race, and did not specifically evidence either Hcy or oxLDL accumulation in such challenging sporting events.