CrossFit is a discipline with high training and nutritional requirements. To date, there is only scarce data evaluating nutrition among CrossFit training and they mostly focus on selected nutritional interventions. Therefore, the purpose of this descriptive study was the assessment of dietary intake and nutritional status in a selected group of CrossFit-trained participants. The study consisted of 62 CrossFit athletes (31 men and 31 women, aged 31.0 ± 5.2 and 30.0 ± 4.3 years, respectively). Body composition was analyzed by electrical bioimpedance. Dietary intake was assessed using a standardized 3-day food record. Body fat percentage for females and males was 20.3 ± 4.3% and 13.7 ± 3.3% respectively. The energy intake in the diet was lower (~1700 kcal in women and ~2300 kcal in men) than the recommended demand. Moreover, low consumption of carbohydrates was stated, as well as an inadequate intake of folate, vitamin E (in women), and minerals, such as Fe and Ca (in women). The energy, carbohydrate, iron, and calcium intake in the CrossFit participants’ diet was too low in comparison to recommendations. It seems justified to educate athletes and coaches about nutritional habits, and individual energy and nutrients requirements.

Exposure to high-altitude hypoxia causes physiological and metabolic adaptive changes by disturbing homeostasis. Hypoxia-related changes in skeletal muscle affect the closely interconnected energy and regeneration processes. The balance between protein synthesis and degradation in the skeletal muscle is regulated by several molecules such as myostatin, cytokines, vitamin D, and irisin. This study investigates changes in irisin and myostatin levels in male climbers after a 2-week high-altitude expedition, and their association with 25(OH)D and indices of inflammatory processes. The study was performed in 8 men aged between 23 and 31 years, who participated in a 2-week climbing expedition in the Alps. The measurements of body composition and serum concentrations of irisin, myostatin, 25(OH)D, interleukin-6, myoglobin, high-sensitivity C-reactive protein, osteoprotegerin, and high-sensitivity soluble receptor activator of NF-κB ligand (sRANKL) were performed before and after expedition. A 2-week exposure to hypobaric hypoxia caused significant decrease in body mass, body mass index (BMI), free fat mass and irisin, 25-Hydroxyvitamin D levels. On the other hand, significant increase in the levels of myoglobin, high-sensitivity C-reactive protein, interleukin-6, and osteoprotegerin were noted. The observed correlations of irisin with 25(OH)D levels, as well as myostatin levels with inflammatory markers and the OPG/RANKL ratio indicate that these myokines may be involved in the energy-related processes and skeletal muscle regeneration in response to 2-week exposure to hypobaric hypoxia.

Kasprzak, Zbigniew, Ewa Śliwicka, Karol Hennig, Łucja Pilaczyńska-Szcześniak, Anna Huta-Osiecka, and Alicja Nowak. Vitamin D, iron metabolism, and diet in alpinists during a 2-week high-altitude climb. High Alt Med Biol 16:230–235, 2015.—A defensive mechanism against hypobaric hypoxia at high altitude is erythropoesis. Some authors point to the contribution of vitamin D to the regulation of this process. The aim of the present study was to assess the 25-hydroxycholecalciferol (25(OH)D) level and its associations with iron metabolic and inflammatory indices in participants of a 2-week mountaineering expedition. The study sample included 9 alpinists practicing recreational mountain climbing. Every 2 or 3 days they set up a different base between 3200 and 3616 m with the intention of climbing 4000 m peaks in the Mont Blanc massif. Before their departure for the mountains and 2 days after returning to the sea level anthropometric parameters, hematological parameters, serum levels of 25(OH)D and iron metabolic indices were measured in all the participants. The composition of the participants' diet was also evaluated. The comparative analysis showed a significant decrease in body mass, BMI values, total iron, and 25(OH)D concentrations (p<0.05). Also significant increases in unsaturated iron-binding capacity, hematocrit, and C-reactive protein concentrations (p<0.05) were found. It can be concluded that the 2-week climbing expedition contributed to the reduction of 25(OH)D levels and these changes were associated with modulation of immune processes. Moreover, the climbers' diet requires some serious modifications.

Skeletal muscle and adipose tissue play an important role in maintaining metabolic homeostasis and thermogenesis. We aimed to investigate the effects of single and repeated exposure to whole-body cryotherapy in volunteers with different physical fitness levels on 25-hydroxyvitamin D (25(OH)D) and myokines. The study included 22 healthy male volunteers (mean age: 21 ± 1.17 years), who underwent 10 consecutive sessions in a cryogenic chamber once daily (3 minutes, −110 °C). Blood samples were collected before and 30 minutes and 24 hours after the first and last cryotherapy sessions. Prior to treatment, body composition and physical fitness levels were measured. After 10 cryotherapy treatments, significant changes were found in myostatin concentrations in the low physical fitness level (LPhL) group. The 25(OH)D levels were increased in the high physical fitness level (HPhL) group and decreased in the LPhL group. The HPhL group had significant changes in the level of high-sensitivity interleukin-6 after the first treatment. The LPhL group had significant changes in 25(OH)D, irisin, and myostatin levels after the tenth treatment. Our data demonstrated that in healthy young men, cryotherapy affects 25(OH)D levels, but they were small and transient. The body’s response to a series of 10 cryotherapy treatments is modified by physical fitness level.

In recent years, there has been increasing interest in the homeostatic response to extreme exercises, especially in the integrated function of muscle and bone. The aim of this study was to evaluate the effects of a marathon race on selected myokines and sclerostin in 10 male recreational runners (mean age 41 ± 7.7 years). Body composition, bone mineral density (BMD), and the serum concentration of myostatin, irisin, sclerostin, osteoprotegerin (OPG), 25-hydroxyvitamin D (25(OH)D), parathyroid hormone (PTH), high-sensitivity interleukin-6 (hsIL-6), tumor necrosis factor α (TNFα), high-sensitivity C-reactive protein (hsCRP) and myoglobin, were determined 24 h before and 24 h and 72 h after a marathon race. Post-marathon increases were observed in the levels of myostatin (1.2-fold), OPG (1.5-fold), and PTH (1.3-fold), hsIL-6 (1.9-fold), myoglobin (4.1-fold), hsCRP (fivefold), TNFα (2.6-fold), after 24 h; and in myostatin (1.2-fold), irisin (1.1-fold), sclerostin (1.3-fold), OPG (1.3-fold), and PTH (1.4-fold), hsIL-6 (1.4-fold), TNFα (1.9-fold), after 72 h compared to the baseline level. The results show that in response to the marathon run, a complex network of endocrine interactions is initiated. Further research is needed to fully elucidate the long-term impact of prolonged high intensity exercise on the human body.