Low-volume high intensity interval training is sufficient to ameliorate the severity of the metabolic syndrome
- Authors: Ramos, Joyce , Dalleck, Lance , Borrani, Fabio , Beetham, Kassia , Wallen, Matthew , Mallard, Alistair , Clark, Bronwyn , Gomersall, Sjaan , Keating, Shelley , Fassett, Robert , Coombes, Jeff
- Date: 2017
- Type: Text , Journal article
- Relation: Metabolic Syndrome and Related Disorders Vol. 15, no. 7 (2017), p. 319-328
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- Description: BACKGROUND: High-intensity interval training (HIIT) is superior to moderate-intensity continuous training (MICT) at improving cardiometabolic risk. However, the optimal volume of HIIT to reduce the severity of the metabolic syndrome (MetS) has yet to be investigated. The aim of this study was to examine the impact of different volumes of HIIT and MICT on MetS severity (MetS z-score). METHODS: This was a substudy of the "Exercise in prevention of Metabolic Syndrome" (EX-MET) multicenter trial, reporting data collected at the Brisbane site. Ninety-nine adults diagnosed with MetS were randomized to one of the following 16-week interventions: (1) MICT [n = 34, 30 min at 60%-70% heart rate (HR) peak/session, 150 min/week]; (2) 4HIIT (n = 34, 4 × 4 min bouts at 85%-95% HR peak, interspersed with 3 min active recovery at 50%-70% HR peak, 114 min/week); or (3) 1HIIT (n = 31, 1 × 4 min bout at 85%-95% HR peak, 51 min/week). Z-scores were derived from levels of MetS risk factors before and after the intervention. RESULTS: Eighty-one participants completed post-testing (MICT, n = 26; 4HIIT, n = 28, 1HIIT, n = 27). After excluding 16 participants who had a change in medication dosage or type during the intervention, a total of 65 participants were included in the analysis [MICT, n = 22, age 55 ± 10 years, body mass index (BMI) 32 ± 6 kg/m; 4HIIT, n = 22, 56 ± 10 years, 35 ± 9 kg/m2; 1HIIT, n = 21, 57 ± 8 years, 32 ± 5 kg/m). MetS severity reduced following all interventions (pre- to post-MetS z-score: MICT, 1.80 ± 1.93 to 0.90 ± 1.93; 4HIIT, 2.75 ± 2.56 to 2.17 ± 2.71; 1HIIT, 2.48 ± 3.38 to 0.84 ± 2.98), with no significant differences between groups. There were no reported adverse events that were directly related to the exercise interventions. CONCLUSIONS: Low-volume HIIT (51 min/week) was as effective as high-volume HIIT (114 min/week) and MICT (150 min/week) in ameliorating MetS severity.
NAFLD in clinical practice : Can simple blood and anthropometric markers be used to detect change in liver fat measured by 1H-MRS?
- Authors: Keating, Shelley , Parker, Helen , Hickman, Ingrid , Gomersall, Sjaan , Wallen, Matthew , Coombes, Jeff , Macdonald, Graeme , George, Jacob , Johnson, Nathan
- Date: 2017
- Type: Text , Journal article
- Relation: Liver International Vol. 37, no. 12 (2017), p.1907-1915
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- Description: Background & Aims: Research in NAFLD management is commonly based on quantitative assessment of liver fat by proton-magnetic resonance spectroscopy (1H-MRS), and translation of this into clinical practice is currently limited by availability and expense. Novel steatosis biomarkers have been proposed for the prediction of liver fatness; however, whether these are suitable for detecting changes in liver fat is unknown. We aimed to determine the accuracy of these indices, and waist circumference (WC), in quantifying longitudinal change in 1H-MRS-quantified liver fat. Methods: We performed a secondary analysis using data from 97 overweight/obese adults (age: 39.7±11.5 years, body mass index: 30.7±4.4 kg/m2, liver fat: 6.0±4.8%, 65% male) who completed either an 8-week exercise or 12-week nutraceutical intervention, with varying degrees of change in liver fat. Baseline and post-intervention measures were liver fat (1H-MRS), NAFLD Liver Fat Score, Liver Fat Equation (LFE), Fatty Liver Index (FLI), Hepatic Steatosis Index (HSI), the Visceral Adiposity Index (VAI) and WC. Results: Only the change in HSI, FLI and WC was associated with change in liver fat; however, correlations were weak to moderate. There was no agreement between the LFE and 1H-MRS for detecting liver fat change. Only change in WC significantly affected change in liver fat (P<.001), and WC AUROC for the presence of steatosis was 0.65 and 0.78 for men and women respectively.Conclusions: Novel indices are limited in their ability to detect longitudinal change in liver fat. Waist circumference may offer modest utility as a surrogate to infer liver fat change with lifestyle interventions.
- Description: Background & Aims: Research in NAFLD management is commonly based on quantitative assessment of liver fat by proton-magnetic resonance spectroscopy (1H-MRS), and translation of this into clinical practice is currently limited by availability and expense. Novel steatosis biomarkers have been proposed for the prediction of liver fatness; however, whether these are suitable for detecting changes in liver fat is unknown. We aimed to determine the accuracy of these indices, and waist circumference (WC), in quantifying longitudinal change in 1H-MRS-quantified liver fat. Methods: We performed a secondary analysis using data from 97 overweight/obese adults (age: 39.7±11.5 years, body mass index: 30.7±4.4 kg/m2, liver fat: 6.0±4.8%, 65% male) who completed either an 8-week exercise or 12-week nutraceutical intervention, with varying degrees of change in liver fat. Baseline and post-intervention measures were liver fat (1H-MRS), NAFLD Liver Fat Score, Liver Fat Equation (LFE), Fatty Liver Index (FLI), Hepatic Steatosis Index (HSI), the Visceral Adiposity Index (VAI) and WC. Results: Only the change in HSI, FLI and WC was associated with change in liver fat; however, correlations were weak to moderate. There was no agreement between the LFE and 1H-MRS for detecting liver fat change. Only change in WC significantly affected change in liver fat (
Accuracy of heart rate watches: Implications for weight management
- Authors: Wallen, Matthew , Gomersall, Sjaan , Keating, Shelley , Wisløff, Og Ulrik , Coombes, Jeff
- Date: 2016
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 11, no. 5 (2016), p.
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- Description: Background: Wrist-worn monitors claim to provide accurate measures of heart rate and energy expenditure. People wishing to lose weight use these devices to monitor energy balance, however the accuracy of these devices to measure such parameters has not been established. Aim: To determine the accuracy of four wrist-worn devices (Apple Watch, Fitbit Charge HR, Samsung Gear S and Mio Alpha) to measure heart rate and energy expenditure at rest and during exercise. Methods: Twenty-two healthy volunteers (50% female; aged 24 ± 5.6 years) completed ∼1-hr protocols involving supine and seated rest, walking and running on a treadmill and cycling on an ergometer. Data from the devices collected during the protocol were compared with reference methods: electrocardiography (heart rate) and indirect calorimetry (energy expenditure). Results: None of the devices performed significantly better overall, however heart rate was consistently more accurate than energy expenditure across all four devices. Correlations between the devices and reference methods were moderate to strong for heart rate (0.67-0.95 [0.35 to 0.98]) and weak to strong for energy expenditure (0.16-0.86 [-0.25 to 0.95]). All devices underestimated both outcomes compared to reference methods. The percentage error for heart rate was small across the devices (range: 1-9%) but greater for energy expenditure (9-43%). Similarly, limits of agreement were considerably narrower for heart rate (ranging from -27.3 to 13.1 bpm) than energy expenditure (ranging from -266.7 to 65.7 kcals) across devices. Conclusion: These devices accurately measure heart rate. However, estimates of energy expenditure are poor and would have implications for people using these devices for weight loss. © 2016 Wallen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.