Athletes experience high total energy expenditure; therefore, it is important to understand the characteristics of the components contributing to this expenditure. To date, few studies have examined particularly the volume and activity intensity of non-exercise activity thermogenesis (NEAT) in athletes compared to non-athletes under real-life conditions. This study aimed to determine the volume and intensity of NEAT in collegiate athletes. Highly trained Japanese male collegiate athletes (n = 21) and healthy sedentary male students (n = 12) participated in this study. All measurements were obtained during the athletes' regular training season under real-life conditions. NEAT was calculated using metabolic equivalent (MET) data using an accelerometer. The participants were asked to wear a validated triaxial accelerometer for 7 consecutive days. Physical activity intensity in NEAT was classified into sedentary (1.0–1.5 METs), light (1.6–2.9 METs), moderate (3.0–5.9 METs), and vigorous (≥6 METs) intensity. NEAT was significantly higher in athletes than in non-athletes (821 ± 185 kcal/day vs. 643 ± 164 kcal/day, p = 0.009). Although there was no significant difference in NEAT values relative to body weight (BW) between the groups (athletes: 10.5 ± 1.7 kcal/kg BW/day, non-athletes: 10.4 ± 2.2 kcal/kg BW/day, p = 0.939), NEAT to BW per hour was significantly higher in athletes than in non-athletes (0.81 ± 0.16 kcal/kg BW/h vs. 0.66 ± 0.12 kcal/kg BW/h, p = 0.013). Athletes spent less time in sedentary and light-intensity activities and more time in vigorous-intensity activities than non-athletes (p < 0.001, p = 0.019, and p = 0.030, respectively). Athletes expended more energy on vigorous- and moderate-intensity activities than non-athletes (p = 0.009 and p = 0.011, respectively). This study suggests that athletes' NEAT relative to BW per day is similar to that of non-athletes, but athletes spend less time on NEAT, which makes them more active in their daily lives when not exercising and sleeping.

令和元年国民健康栄養調査によると、20代女性の朝食欠食率は18.1%、30歳代では22.4%であり、若年勤労女性の約5名に1名が朝食を欠食している。朝食欠食は若年女性における除脂肪量の低値、骨密度の低下及び主観的体調不良など様々な健康問題に関連することから、糖代謝、脂質代謝及び鉄代謝不良など他の健康問題を誘発するリスクにもなり得ると考えられる。【目的】若年勤労女性を対象に朝食摂取習慣の有無と血液生化学指標との関連を明らかにすることとした。【方法】対象者は正常月経周期を有する若年勤労女性22名であり、朝食摂取群(n=11、年齢30±3歳、BMI20.6±1.8kg/m2)と朝食欠食群(n=11、年齢28±6歳、BMI20.2±1.6kg/m2)に分類した。調査項目は食事記録法によるエネルギー、栄養素及び食品群別摂取量、早朝空腹時の血液検査及び生体電気インピーダンス法による身体組成であり、2群間で各項目を比較した。【結果】朝食欠食群は朝食摂取群と比較してエネルギー(kcal/日)、たんぱく質(g/日)、炭水化物(g/日)及び穀類(g/日)の摂取量が有意に低値を示した。また血液生化学指標において朝食欠食群の血清フェリチン(ng/dL)及びMCH(pg)が有意に低値を示した。血清フェリチン<20ng/dL及びMCH<28.6pgを鉄欠乏のスクリーニングとすると両血中指標ともに朝食欠食群は朝食摂取群と比較してカットオフ値を下回る者の割合が高値を示した。【結論】朝食摂取習慣の有無は若年女性における鉄欠乏と関連することが示唆された。潜在性鉄欠乏は本邦の若年女性において罹患率の高い疾病の1つであり、様々な不定愁訴と関連することから、その予防策として朝食摂取の重要性を普及する必要がある。(著者抄録)

Menstrual disorders are health problems in female athletes. It has also been reported that amenorrhea can lead to metabolic suppression. However, studies regarding resting energy expenditure (REE) in Japanese female athletes with menstrual disorders are lacking. The purpose of this study was to investigate whether REE was suppressed in female Japanese athletes with menstrual disorders. In total, 22 highly trained intercollegiate athletes participated in this study; and body composition, REE, thyroid and reproductive hormone levels, and nutritional intake levels were measured. Predicted REE (REEp) was calculated using two different equations based on fat-free mass (FFM) and organ-tissue mass measured by dual-energy X-ray absorptiometry (DXA). Individuals with menstrual disorders (MD group) had significantly lower height, body weight, and fat mass than those in the eumenorrheic (EU) group; however, the FFM did not differ between the groups. Both the measured REE (REEm) and REEm adjusted for FFM in the MD group were lower than those in the EU group. The REEm to REEp ratio, which indicates energy deficiency, was also lower in the MD group. In addition, although the MD group had lower triiodothyronine and progesterone levels, they were still within the normal range. Japanese female athletes with menstrual disorders may have lower REE than eumenorrheic athletes, even if thyroid and reproductive hormones are within the normal range.

卵胞ホルモンと黄体ホルモンは女性の月経周期内で大きく変化し、一般女性においては卵胞期と比較して黄体期には総エネルギー摂取量(TEI)が増加することが知られている。このことから、卵胞期と黄体期でエナジー・アベイラビリティー(EA)が変化する可能性が考えられる。したがって本研究は、大学生女性アスリートにおける月経周期によるEAの変化を明らかにすることを目的とした。対象は、正常月経周期を有する大学生女性アスリート11名であった。排卵検査を用いて卵胞期と黄体期を特定し、各期に食事記録法によるTEI、心拍数法による運動時エネルギー消費量(EEE)、DXA法による身体組成、血清中のホルモン濃度を測定した。EAは、TEIからnet-EEEを差し引き、除脂肪量(FFM)で除して求めた。その結果、卵胞期と黄体期のEAに有意な差は認められなかった。黄体期の血清プロゲステロン濃度は10.4(6.0-15.9)ng/mLであり、上昇度合いが低かった。周期内のホルモンの変動が小さいことから、卵胞期と黄体期のTEIに有意な差が認められず、EAにも有意な差が認められなかったと考えられる。正常月経周期を有する大学生女性アスリートにおいては、周期によるEAに変化は認められないことが明らかとなった。(著者抄録)