Alan J. Mccubbin

Monash University (Australia) · Department of Nutrition Dietetics and Food

Evidence suggests the focus for sodium replacement during exercise should be maintenance of plasma sodium concentration ([Na⁺]plasma) for any given total body water (TBW) volume. The sodium intake to achieve stable [Na⁺]plasma given known fluid and electrolyte intakes and losses can be mathematically estimated. Therefore the aim of this investigati...

Exertional heat stress presents a different acute challenge to salt balance compared to at rest. Sodium (Na⁺) and chloride (Cl⁻) losses during exercise are overwhelmingly driven by eccrine sweat glands (the “leader”), with minimal urinary excretion. Total salt losses are therefore largely influenced by thermoregulatory need, although adaptations fr...

It is the position of Sports Dietitians Australia (SDA) that exercise in hot and/or humid environments, or with significant clothing and/or equipment that prevents body heat loss (i.e., exertional heat stress), provides significant challenges to an athlete’s nutritional status, health, and performance. Exertional heat stress, especially when prolon...

Purpose To determine the impact of altering dietary sodium intake for 3 days preceding exercise on sweat sodium concentration [Na⁺], and cardiovascular and thermoregulatory variables. Methods Fifteen male endurance athletes (runners n = 8, cyclists n = 7) consumed a low (LNa, 15 mg kg⁻¹ day⁻¹) or high (HNa, 100 mg kg⁻¹ day⁻¹) sodium diet, or their...

Sports nutrition guidelines frequently encourage sodium ingestion during endurance exercise, and much work has been undertaken to quantify sweat sodium losses during exercise. However, current guidelines for sodium do not recommend specific quantities, nor provide justification for the effectiveness of sodium to improve endurance performance. A sys...

Purpose : To investigate the effect of personalized sweat sodium replacement on drinking behavior, sodium and water balance, and thermophysiological responses during and after ultraendurance running in hot conditions. Methods : Nine participants (7 male, 2 female) completed two 5-hour treadmill runs (60% maximum oxygen uptake, 30°C ambient temperat...

Introduction A systematic literature search was undertaken to assess the impact of pre-, pro-, and syn-biotic supplementation on measures of gastrointestinal status at rest and in response to acute exercise. Methods Six databases (Ovid MEDLINE, EMBASE, Cinahl, SportsDISCUS, Web of Science, and Scopus) were used. Included were human research studie...

This case reports peripheral blood mononuclear cell (PBMC) transcriptomic changes in a pair of male monozygotic pediatric twins with metabolic syndrome (MetS) undertaking assisted weight loss. These 14-year-old boys presented with similar baseline biochemistry and body composition. After a 16-week weight-loss intervention, percent body weight loss...

Objectives This study aimed to determine the impact of running and cycling exercise modalities on the magnitude of exercise-induced gastrointestinal syndrome (EIGS) and associated gastrointestinal symptoms (GIS). Design Parallel group trial design. Methods Twenty-eight endurance athletes (male n = 14, female n = 14) completed 2 h running at 55 %...

Using metadata from previously published research, this investigation sought to explore: (1) whole-body total carbohydrate and fat oxidation rates of endurance (e.g., half and full marathon) and ultra-endurance runners during an incremental exercise test to volitional exhaustion and steady-state exercise while consuming a mixed macronutrient diet a...

Background: Evidence suggests the focus for sodium replacement during exercise should be maintenance of plasma sodium concentration ([Na+]plasma). The sodium intake to achieve stable [Na+]plasma given known fluid and electrolyte intakes and losses can be mathematically estimated. Aim: To model sodium requirements of athletes competing in soccer,...

Background: ‘Exercise-induced gastrointestinal syndrome’ (EIGS) refers to gastrointestinal disturbances in response to exercise, commonly experienced by individuals undertaking strenuous exercise. Aim: Systematically review the literature into the beneficial or detrimental effect/s of pre-, pro-, and syn-biotics supplementation on gastrointestinal...

Objective.—The study aimed to comprehensively determine the impact of consuming a dairy milk beverage after prolonged strenuous exercise on hydration status. Methods.—Using a randomised crossover study design, 11 endurance male athletes consumed a chocolate flavoured dairy milk beverage (CM: 1.2g/kg carbohydrate and 0.4g/kg protein) or a carbohydra...

Objective.—The study aimed to determine the impact of consuming a dairy milk beverage after prolonged strenuous exercise on gastrointestinal Methods.—Using a randomised crossover study design, 11 endurance male athletes consumed a chocolate flavoured dairy milk beverage (CM: 1.2g/kg carbohydrate and 0.4g/kg protein) or a carbohydrate-electrolyte be...

The impact of a carbohydrate-electrolyte solution with sodium alginate and pectin for hydrogel formation (CES-HGel), was compared to a standard CES with otherwise matched ingredients (CES-Std), for blood glucose, substrate oxidation, gastrointestinal symptoms (GIS; nausea, belching, bloating, pain, regurgitation, flatulence, urge to defecate, and d...

Exercise-induced gastrointestinal syndrome (EIGS) is a common characteristic of exercise. The causes appear to be multi-factorial in origin, but stem primarily from splanchnic hypoperfusion and increased sympathetic drive. These primary causes can lead to secondary outcomes that include increased intestinal epithelial injury and gastrointestinal hy...

There is little information describing how endurance athletes perceive sodium intake in relation to training and competition. Using an online questionnaire, this study assessed the beliefs, information sources, and intended practices regarding sodium ingestion for training and competition. Endurance athletes (n = 344) from six English-speaking coun...

To assess the impact of rationed versus full estimated energy provisions on markers of physiological strain in response to a simulated 250km multistage ultramarathon (MSUM), on two separate occasions, the ultraendurance runner performed a laboratory simulated MSUM, with rationed (RP: 3303±75 kcal⋅day-1) and full (FP: 7156±359 kcal⋅day-1) provisions...

The collection, processing, and analysis of sweat samples to determine sodium losses during endurance exercise is common amongst sports and exercise nutrition practitioners, and necessary for researchers investigating sodium losses and replacement strategies. Several factors influence sweat sodium concentration ([Na+]) that need to be controlled or...

This case study describes the nutrition plans, intakes and experiences of five ultra-marathon runners who completed the Marathon des Sables in 2011 and 2013; age 37 (28-43) y, height 184 (180-190) cm, body mass 77.5 (71-85.5) kg, marathon personal best 3:08 (2:40-3:32). MdS is a seven-day, six-stage ultrarunning stage race held in the Sahara Desert...

Objective: Clinical trials have demonstrated the health benefits of weight loss for diabetic populations. However clinical programs often attract patients with more co-morbidities and greater diabetes distress leading to poorer self-care and less weight reduction. This study compared the efficacy of a hospital-based lifestyle change program to impr...