Applied Physiology, Nutrition, and Metabolism
ISSN / EISSN : 1715-5312 / 1715-5320
Published by: Canadian Science Publishing (10.1139)
Total articles ≅ 2,848
Latest articles in this journal
Published: 15 October 2021
Applied Physiology, Nutrition, and Metabolism pp 1-1; https://doi.org/10.1139/apnm-2021-0669
Published: 12 October 2021
Applied Physiology, Nutrition, and Metabolism; https://doi.org/10.1139/apnm-2021-0383
To assess the physiological demand of including high-intensity efforts during continuous exercise, we designed a randomized crossover study, where 12 physically active young males executed three different exercises in random order: FATmax - continuous exercise at the highest fat oxidation zone (FATmax); 2min-130% - FATmax interspersed by a 2-min bout at 130% of the maximal oxygen uptake associated intensity (iV̇O2max); and 20s:10s-170% - FATmax interspersed by four 20-s bouts at 170%iV̇O2max interpolated by 10s of passive recovery. We measured oxygen uptake (V̇O2), blood lactate concentration ([LAC]), respiratory exchange rate (RER), fat and carbohydrate (CHO) oxidation. For statistical analyses, repeated measures ANOVA was applied. Although no differences were found for average V̇O2 or carbohydrate oxidation rate, the post-exercise fat oxidation rate was 37.5% and 50% higher during 2min-130% and 20s:10s-170%, respectively, compared to FATmax, which also presented lower values of RER during exercise compared to 2min-130% and 20s:10s-170% (p<0.001 in both), and higher values post-exercise (p=0.04 and p=0.002, respectively). The [LAC] was higher during exercise when high-intensity bouts were applied (p<0.001 for both) and higher post-exercise on the intermittent one compared to FATmax (p=0.016). The inclusion of high-intensity efforts during moderate-intensity continuous exercise promoted higher physiological demand and post-exercise fat oxidation. Novelty bullets • The inclusion of 2-min efforts modifies continuous exercise demands • Maximal efforts can increase post-exercise fat oxidation • 2-min maximal efforts, continuous or intermittent, presents similar demands
Published: 12 October 2021
Applied Physiology, Nutrition, and Metabolism; https://doi.org/10.1139/apnm-2020-1075
Food insecurity disproportionately impacts Aboriginal and Torres Strait Islander Australians. This review sought to investigate research and evaluations of programs and interventions implemented to address food insecurity among Aboriginal and Torres Strait Islander communities. A rapid review was conducted to collate the available research from six databases. The search was conducted in May 2020. Search constructs related to food insecurity, Aboriginal and Torres Strait Islander people, and Australia. 25 publications were included in this review, 24 reported on an intervention, while nine were evaluations of an intervention. Interventions included behaviour change projects, including projects that sought to change purchasing and cooking behaviours, school-based education programs, and gardening programs. In general, the studies included in this sample were small, and lacked a systematic consideration of the factors that shape the experience of food insecurity among Aboriginal and Torres Strait Islander people specifically. Based on the findings of this review, authors suggest greater consideration to the systematic determinants of food insecurity among Aboriginal and Torres Strait Islander communities to have lasting and sustainable impact on food insecurity. This review has been registered with the international prospective register of systematic reviews (PROSPERO: CRD42020183709). Novelty bullets • Food insecurity among Aboriginal and Torres Strait Islander people poses significant risk to health and wellbeing. • Small scale food security interventions may not provide ongoing and sustained impact. • Any intervention to promote food security will need to involve Aboriginal and Torres Strait Islander people and be sustained once external parties have left.
Published: 6 October 2021
Applied Physiology, Nutrition, and Metabolism; https://doi.org/10.1139/apnm-2020-0928
Higher sodium (Na+) intakes are associated with higher blood pressure (BP). Whether this relationship is stronger with diet-dependent acid load (DAL) and in patients with diagnosed hypertension or normal BP is not well determined. We studied 170 postmenopausal women randomized to potassium bicarbonate or placebo till 36 months where 24-hour urine and arterialized blood were collected. We investigated the association of DAL estimated as urinary potential renal acid load (UPRAL) and mean arterial pressure (MAP) using mixed-effects model, adjusting for age, anthropometrics, creatinine clearance, and treatment. Adjusted regression estimates for change in Na+ and UPRAL on MAP after 12 months follow-up were calculated, and further adjustments were made for change in potassium (K+) and body mass index (BMI). MAP was inversely associated with UPRAL (β [95% CI]:-0.11[-0.25,-0.001]). There was effect modification by hypertension (p-interaction=0.04); MAP decreased significantly in normotensives but the association was not significant in hypertensives. A decrease of 0.70 mmHg in MAP (0.13,1.69) per 50 mmol/24 hr reduction in Na+ was noted when the model was adjusted for change in K+. Our results with UPRAL exhibited stronger dose-response for MAP, which remained significant after adjustment for BMI. UPRAL was independently associated with MAP even after adjustment for potential confounders, and the data showed this association to be more pronounced in normotensives. Novelty: • First longitudinal study on the association of UPRAL and MAP • Association was a more robust relationship than between U[Na/K] ratio and MAP • UPRAL may play a significant role in the pathogenesis of primary hypertension
Published: 6 October 2021
Applied Physiology, Nutrition, and Metabolism pp 1-11; https://doi.org/10.1139/apnm-2021-0110
This systematic review and meta-analysis determined whether the ergogenic effects of branched-chain amino acids (BCAA) ameliorated markers of muscle damage and performance following strenuous exercise. In total, 25 studies were included, consisting of 479 participants (age 24.3 ± 8.3 years, height 1.73 ± 0.06 m, body mass 70.8 ± 9.5 kg, females 26.3%). These studies were rated as fair to excellent following the PEDro scale. The outcome measures were compared between the BCAA and placebo conditions at 24 and 48 hours following muscle-damaging exercises, using standardised mean differences and associated p-values via forest plots. Our meta-analysis demonstrated significantly lower levels of indirect muscle damage markers (creatine kinase, lactate dehydrogenase and myoglobin) at 48 hours post-exercise (standardised mean difference [SMD] = −0.41; p < 0.05) for the BCAA than placebo conditions, whilst muscle soreness was significant at 24 hours post-exercise (SMD = −0.28 ≤ d ≤ −0.61; p < 0.05) and 48 hours post-exercise (SMD = −0.41 ≤ d≤ −0.92; p < 0.01). However, no significant differences were identified between the BCAA and placebo conditions for muscle performance at 24 or 48 hours post-exercise (SMD = 0.08 ≤ d ≤ 0.21; p > 0.05). Overall, BCAA reduced the level of muscle damage biomarkers and muscle soreness following muscle-damaging exercises. However, the potential benefits of BCAA for muscle performance recovery is questionable and warrants further investigation to determine the practicality of BCAA for ameliorating muscle damage symptoms in diverse populations. PROSPERO registration number: CRD42020191248. Novelty: BCAA reduces the level of creatine kinase and muscle soreness following strenuous exercise with a dose–response relationship. BCAA does not accelerate recovery for muscle performance.
Published: 5 October 2021
Applied Physiology, Nutrition, and Metabolism; https://doi.org/10.1139/apnm-2021-0374
It has been shown that the critical speed (CS) predicted from a perceptually self-regulated 10-min submaximal treadmill test (T10) is reliable and closely matches the CS estimated from conventional methods. To assess the relationship between the T10 and 5-km and 10-km running performances, 36 recreational runners (mean SD: age: 32.2 ± 6.2 years, height: 173.2 ± 7.3 cm, weight: 70.9 ± 8.8 kg, V̇O2max: 53.3 ± 6.1 mL.kg-1.min-1) performed a ramp incremental test and two T10 tests (the first as a familiarization trial). Results showed that the T10 CS (3.9 ± 0.44 m.s-1) was significantly correlated with runners’ last 6 months best performances in 5-km (20.3 ± 2.7 min; r = -0.90) and 10-km (42.7 ± 5.7 min; r = -0.91), the V̇O2max (r = 0.75), the speed associated with the gas exchange threshold (vGET: 3.38 ± 0.36 m.s-1; r = 0.76), the speed associated with the second ventilatory threshold (vVT2: 4.15 ± 0.49 m.s-1; r = 0.84), and the speed associated with the V̇O2max (vV̇O2max: 4.78 ± 0.54 m.s-1; r = 0.87). Moreover, 79% and 83% of the variance in 5-km and 10-km performances could be explained solely by the CS predicted from the T10. Results evidenced the strong relationship and practical performance relevance of the T10 CS test. Novelty: • Critical speed derived from a 10-min submaximal treadmill test (T10) is significantly correlated with 5-km and 10-km running performances • The T10 critical speed test may represent a useful tool for assessing running performance capabilities
Published: 1 October 2021
Applied Physiology, Nutrition, and Metabolism, Volume 46; https://doi.org/10.1139/apnm-2021-0562
Published: 1 October 2021
Applied Physiology, Nutrition, and Metabolism, Volume 46, pp 1179-1188; https://doi.org/10.1139/apnm-2020-0880
Low energy availability (EA) suppresses many physiological processes, including ovarian function in female athletes. Low EA could also predispose athletes to develop a state of overreaching. This study compared the changes in ad libitum energy intake (EI), exercise energy expenditure (ExEE), and EA among runners completing a training overload (TO) phase. We tested the hypothesis that runners becoming overreached would show decreased EA, suppressed ovarian function and plasma leptin, compared with well-adapted (WA) runners. After 1 menstrual cycle (baseline), 16 eumenorrheic runners performed 4 weeks of TO followed by a 2-week recovery (131 ± 3% and 63 ± 6% of baseline running volume, respectively). Seven-day ExEE, EI, running performance (RUNperf) and plasma leptin concentration were assessed for each phase. Salivary estradiol concentration was measured daily. Urinary luteinizing hormone concentration tests confirmed ovulation. Nine runners adapted positively to TO (WA, ΔRUNperf: +4 ± 2%); 7 were non-functionally overreached (NFOR; ΔRUNperf: −9 ± 2%) as RUNperf remained suppressed after the recovery period. WA increased EI during TO, maintaining their baseline EA despite a large increase in ExEE (ΔEA = +1.9 ± 1.3 kcal·kg fat free mass (FFM)−1·d−1, P = 0.17). By contrast, NFOR showed no change in EI, leading to decreased EA (ΔEA = −5.6 ± 2.1 kcal·kg FFM−1·d−1, P = 0.04). Plasma leptin concentration mid-cycle and luteal salivary estradiol concentration decreased in NFOR only. Contrasting with WA, NFOR failed to maintain baseline EA during TO, resulting in poor performance outcomes and suppressed ovarian function. ClinicalTrials.gov no. NCT02224976. Novelty: Runners adapting positively to training overload (TO) increased ad libitum energy intake, maintaining baseline EA and ovarian function through TO. By contrast, NFOR runners failed to increase energy intake, showing suppressed EA and ovarian function during TO.
Published: 29 September 2021
Applied Physiology, Nutrition, and Metabolism; https://doi.org/10.1139/apnm-2021-0299
Introduction: Patients with colorectal cancer are at risk of malnutrition before surgery. Multimodal prehabilitation (nutrition, exercise, stress reduction) readies patients physically and mentally for their operation. However, it is unclear whether extent of malnutrition influences prehabilitation outcomes. Methods: We conducted a pooled analysis from five 4-week multimodal prehabilitation trials in colorectal cancer surgery (prehabilitation: n=195; control: n=71). Each patient’s nutritional status was evaluated at baseline using the Patient-Generated Subjective Global Assessment (PG-SGA; higher score, greater need for treatment of malnutrition). Functional walking capacity was measured with the six-minute walk test (6MWD) at baseline and before surgery. A multivariable mixed effects logistic regression model evaluated the potential modifying effect of PG-SGA on a clinically meaningful change of >=19m in 6MWD before surgery. Results: Multimodal prehabilitation increased the odds by 3.4 times that colorectal cancer patients improved their 6MWD before surgery as compared to control (95%CI:1.6 to 7.3; P=0.001, n=220). Nutritional status significantly modified this outcome (P=0.007): Neither those patients with PG-SGA>=9 (adjusted odds ratio:1.3; 95% CI: 0.23 to 7.2, P=0.771, n=39) nor PG-SGA <4 (adjusted odds ratio:1.3; 95% CI: 0.5 to 3.8, P=0.574, n=87) improved in 6MWD with prehabilitation. Conclusion: Baseline nutritional status modifies prehabilitation effectiveness before colorectal cancer surgery. Patients with a PG-SGA score 4-8 appear to benefit most (physically) from 4 weeks of multimodal prehabilitation. Novelty bullets: 1) Nutritional status is an effect modifier of prehabilitation physical function outcomes; 2) Patients with a PG-SGA score 4-8 benefited physically from 4 weeks of multimodal prehabilitation.
Published: 29 September 2021
Applied Physiology, Nutrition, and Metabolism; https://doi.org/10.1139/apnm-2021-0459
This study described the whole blood fatty acid profile and Omega-3 Index (O3I) of Australian Army recruits at the commencement and completion of basic military training (BMT). Eighty (80) males (17-34 y, 77.4±13.0 kg, 43.5±4.3 mL/kg/min) and 37 females (17-45 y, 64.3±8.8 kg, 39.3±2.7 mL/kg/min) volunteered to participate (N=117). Whole blood samples of each recruit were collected using a finger prick in weeks 1 and 11 (n=82) and analysed via gas chromatography for the relative proportions of each fatty acid (mean [95% CI]). The macronutrient characteristics of the diet offerings was also determined. At commencement there was a low omega-3 status (sum of omega-3; 4.95% [4.82-5.07]) and O3I (5.03% [4.90-5.16]) and no recruit recorded an O3I >8% (desirable). The omega-6/omega-3 (7.04 [6.85-7.23]) and arachidonic acid / eicosapentaenoic acid (AA/EPA) (18.70 [17.86-19.53]) ratios for the cohort were also undesirable. The BMT mess menu provided a maximum of 190 mg/day of eicosapentaenoic acid (EPA) and 260 mg/day of docosahexaenoic acid (DHA). The O3I of the recruits was lower by week 11 (4.62% [4.51-4.78], p<0.05), the omega-6/omega-3 increased (7.27 [7.07-7.47] p<0.05) and the AA/EPA remained elevated (17.85 [16.89-18.81]). In conclusion, Australian Army recruits’ omega-3 status remained undesirable during BMT and deserves nutritional attention. Novelty Bullets • Australian Army recruits’ Omega-3 Index, at the commencement of BMT, was reflective of the Western-style diet. • The BMT diet offered minimum opportunity for daily EPA and DHA consumption. • Every recruit experienced a further reduction of their Omega-3 Index during BMT.