During the first few months of any new year many struggle to maintain their exercise compliance. Initial motivations are not sustained to support the demands of lifestyle changes. Commonly, the main complaint is not the exercise but the minimal time available to keep up their “ideal” exercise regimen. This perception is often is due in part to the real and perceived occupational, family and social factors that affect our daily lives. For those citing a lack of time as a true determent to fitness, newly-published research may provide some comfort as well as solutions.
A study published in the Journal of Physiology (2013), exercise scientists at Liverpool John Moores University (LJMU) and the University of Birmingham, under the lead of Professor Anton Wagenmakers, investigated methods for saving time in the gym while still maximizing fitness and health-related results. Current recommendations made by the World Health Organization (WHO) and the UK Department of Health state individuals of all ages should engage in at least three to five hours of endurance training each week to increase health/fitness measures while also reducing the risk for chronic diseases and premature mortality. However, as mentioned previously, most people find it difficult to set aside this much time due to a busy schedule. This investigation set to prove that replacing the more common steady-state endurance training with two types of interval training, High-intensity Interval Training (HIT) and Sprint Interval Training (SIT), can make a substantial difference on measures of health and aerobic capacity, while taking less than half the time to complete.
The research team found that three sessions of SIT, lasting a total of 90 min, were just as effective as five sessions of steady-state endurance exercise, lasting a total of five hours (or 300 min), for increasing total body insulin sensitivity. LJMU researcher Matthew Cocks explains, “One mechanism involves improved delivery of insulin and glucose to the skeletal muscle and the other involves improved intramuscular fat utilization. Additionally, we found a reduced stiffness of large arteries which is important in reducing the risk of vascular disease.” On the basis of these as well as earlier findings, Professor Wagenmakers expects that HIT and SIT could be unique alternative exercise modes suitable to prevent many forms of cardiovascular disease, hypertension, diabetes and other age- and obesity-related chronic diseases. LJMU researcher Sam Shepherd explains the protocol, “SIT involves four to six repeated 30 second 'all out' sprints on special laboratory bikes interspersed with 4.5 minutes of very low intensity cycling. Due to the very high workload of the sprints, this method is generally more suitable for experienced exercisers. However, anyone of any age or level of fitness can follow one of the alternative HIT programs which involve 15-60 second bursts of high intensity cycling interspersed with 2-4 minute intervals of low intensity cycling.” Shepherd went on to describe another current investigation at the Sports Centre at the University of Birmingham demonstrating that previously sedentary individuals (ages 25-60) find HIT on spinning bikes significantly more enjoyable and having a more positive influence on mood and feelings of well-being when compared to traditional endurance training.
These findings imply that HIT or SIT may be suitable to achieve sustainable changes in exercise behavior as program adherence is greatly improved when the individual truly enjoys the activity which they engage - and they are not required to spend excessive time reaching a given goal. Another recent study published in the Journal of Applied Physiology further supports short duration training sessions for those who have limited time for exercise, but are willing to engage in higher-intensities to maximize their results. In this investigation, researchers found acute, high-intensity endurance exercise to be more effective than moderate-intensity exercise for decreasing postprandial plasma triglyceride (PPTG) elevation, by increasing fat oxidation. Reducing PPTG elevation can have positive effects on the blood lipid profile in some scenarios, and plays a part in optimizing metabolic preferences that may promote weight loss in the long-term. Now, acute exercise has already been shown to attenuate PPTG elevation; however, the direct contribution of exercise intensity is not clearly understood. The purpose of this study was to thoroughly examine the effects of exercise intensity on PPGT elevation and postprandial fat oxidation.
Six healthy young men were placed in one of three experimental treatment groups: non-exercise control (CON), moderate-intensity exercise (50% VO2peak, for 60 min), or isoenergetic high-intensity exercise (alternating 2 min at 25% and 2 min at 90% VO2peak). The morning after each exercise bout, a standardized meal was provided (16 kcal/kg of body mass; 1.02 g fat/kg, 1.36 g carbohydrate/kg, 0.31 g protein/kg) and measurements of plasma triglycerides, glucose, insulin and β-hydroxybutyrate (an indicator of ketosis) were made while in a fasted condition before the meal, as well as on an hourly basis for a total of six hours postprandial. Indirect calorimetry was used to determine fat oxidation in the fasted condition and two, four and six hours postprandial. Compared to controls, both the moderate intensity and high intensity exercise attenuated PPTG, with high intensity training demonstrating the most drastic effects. Based on the findings, the study team easily concluded that, despite similar energy expenditure, high intensity exercise is more effective than moderate intensity for lowering PPTG and increasing postprandial fat oxidation.
Even if one finds the busy pace of the new year making gym-time seem like a physical impossibility, (or inconvenience to success in other endeavors) he or she can be somewhat reassured by the fact that current research is embracing a foundational concept related to programming: if training frequency goes down, training intensity must go up to maintain or even improve fitness measures. One easy technique involves setting a caloric expenditure goal, and simply striving to accomplish it in the shortest period of time – this creates progressive objectives based on effort and exercise tolerance. A second method can involve setting a caloric expenditure based on total time, and at the end of each week, the participant can simply increase the total calories by around 5%. This ensures a continued improvement but does not require more time to accomplish. Furthermore, adding a competitive component has shown to improve compliance and serves as a quality motivator.