Every year the same thing happens. Spring approaches. Temperatures rise, and little by little, we start shedding layers of clothing until the final summer unveiling. Before the dreaded 'bikini operation' catches us off guard (and with no time to react), it doesn't hurt to clarify some things, such as what is the most effective strategy for losing weight and enhancing fat burning in the gym.
"As a base, with strength training to build a good 'structure': muscle mass. This type of training is shown as the most suitable tool for the development and improvement of the neuromuscular system. It is worth noting that the volume of muscle mass is directly linked to basal metabolic expenditure (the minimum daily expenditure from which each person starts)," asserts Carla Belén Gutiérrez Sánchez, trainer and registered member of COPLEF Madrid No. 55,383.
To date, this specialist states, "We cannot guarantee that there is a 'magic workout' that we can all use to achieve 'all the benefits at once' at a metabolic, physiological level... In short, overall health. What we can affirm is that paying attention to the different metabolic pathways and different basic physical capacities is a good strategy."
Gutiérrez Sánchez delves into her explanation: "When talking about 'metabolic pathway,' we could use the analogy of 'fuel' that we use to obtain our energy. Depending on the type of exercise, the cardiovascular intensity zone, and other training parameters, one metabolic pathway is prioritized over another. We are a vehicle that, depending on these issues, uses one type of fuel or another. When we exercise at an intensity where there is a lot of oxygen present in the energy acquisition process, lipids can be the main source. With less presence, the carbohydrate pathway will have more weight. However, we must be clear that this is not 'black or white' because we are capable of combining 'fuels'."
With this information in mind, it is easy to deduce that "in our weekly training schedules, having sessions or blocks of sessions with changes in intensity zones can be a way to train ourselves to be more efficient in utilizing all our energy sources."
So, how do we organize the workouts? Sessions only for strength or only for cardiovascular work? "In reality, there are no such marked divisions because, in short, when we move, we activate our musculoskeletal and cardiorespiratory systems. Depending on the level, concurrent/mixed/combined training (when resistance work blocks that provide a stimulus for strength gain/improvement are combined with stimuli that lead to cardiovascular system adaptation) can be a very useful tool. When the number of training days reaches at least three sessions per week, and there are already adaptations to physical exercise (higher training level), the division by metabolic pathways or physical capacity can be more interesting."
Let's talk about cardio. Is it true that the widespread belief that fat burning starts after half an hour is true? "Based on the fact that at rest lipids are the main source of energy, when we say that 'fat consumption starts after minute X,' it is not supported. What needs to be understood is that, although at low cardiovascular effort intensities the percentage of energy obtained mainly comes from lipid metabolism, the total expenditure may be low unless extended over time (volume). However, traditional extensive cardiovascular work sessions clash head-on with our current lifestyle in which lack of time is often one of the most limiting factors for physical activity practice, in general."
If, due to the tightness of our schedules, the most suitable (and realistic) strategy is to shorten the session time, what variable do we introduce in exchange for reducing volume? Gutiérrez Sánchez has the answer: "Intensity. However, working at high intensities without being a trained person requires adaptation. Completing short work blocks, with intensities close to 70% and partial recoveries between sets (intervals) is a way to approach what, after an adaptation process, can become a HIIT (High-Intensity Interval Training). The work intervals, in this case, reach 90-100% of cardiorespiratory capacity."
Why are HIIT workouts so effective if our goal is to lose weight or burn fat? "By reducing the duration, obviously, joint impact and stress are reduced. Interval work blocks are also an easy strategy to implement and adapt to the individual characteristics of each person and, therefore, a very applicable tool." And, on top of all this, it is important to add that this type of work boosts calorie burning even hours after the session has ended.
How do we approach strength training? "For training to be considered strength training, the stimulus we provide to our neuromuscular system must be appropriate for this capacity. For example, if we focus on a movement pillar such as sitting and standing up (which in training terms would be a squat), if we can perform the gesture continuously and without recovery time, the work will probably be high metabolically and low in strength. Conversely, if we reduce the number of repetitions by overcoming a higher load in each one (using resistance bands, adopting different positions, or changing supports), the adaptation will focus on our neuromuscular system, improving the ability to recruit fibers (being able to activate more muscle fibers in the same unit of time) and to overcome more resistance (loads)."
And finally, how much can training on an empty stomach help us in this mission to lose fat? "Physical preparation or training requires other areas such as nutrition for better results. Strategies like reducing the intake window (or, conversely, increasing the fasting window) can favor better functioning of our metabolism. However, the effect of these strategies varies from person to person. Training on an empty stomach can help with better lipid digestion in many cases, but it can also happen that we feel weak and lack energy, which reduces the intensity and amount of work in our session. If we want to achieve optimal results in our workouts, we must rely on the nutritional advice of qualified professionals and, of course, avoid trends, false messages, and deceptive advertising to avoid falling into the trap of scientifically unfounded approaches."