Fitness Rush Personal Training Blog



Beneficial Training Window "BTW"

"The window of time directly following a strength or resistance workout"

This time is crucial to maximize the usage of fat after the body's glycogen stores have been depleted through intense strain on muscle fibres from challenging resistance training. 

Studies have shown, glycogen levels will deplete between 30-45 minutes depending on training intensity and previous glucose intake. 

Once these glycogen levels are drained, the body switches to an alternative energy system - Fat.

Further studies prove that reaching an optimal level of approximately 65% of a persons maximum heart rate, can use up to 50% more fat as energy compared to any other heart rate percentage.

It is advised to use a piece of equipment which can help maintain a steady heart rate to maximise fat usage for a substantial amount of time. 

A walk on a treadmill (or outside) or an exercise bike would be sensible choices due to their ability to change levels or speed instantly. A Rowing Machine for example would be difficult to regulate due to the amount of muscles working throughout the exercise. 

Timing also has an important role to play when it comes to the body's next choice of energy usage, which is Protein (or Muscle as we know it).

If gaining or retaining muscle mass is the main target, it is crucial that the cardiovascular exercise does not majorly overrun into the use of muscle, possibly resulting in the adverse affect. 

It is difficult to say how long the beneficial fat usage training window is due to many variables but it is advisable to steadily increase exercise time over a gradual period as not to encroach on muscle mass too early in the hypertrophy (muscle building) phase of a training programme. 

Start with a time which is easily sustainable and build upon it steadily. 

For example (not including warm-up, cool-down and stretching):

Workout 1:
30-40 minutes strength
10-15 minutes steady state cardio
Workout 2:
30-40 minutes strength
15-20 minutes steady state cardio


Workout 3:
35-40 minutes strength
15-25 minutes steady state cardio


Workout 4:
35-40 minutes strength
20-30 minutes steady state cardio


Workout 5:
35-45 minutes strength
20-35 minutes steady state cardio


Noticeably, the strength training time rarely changes, as the glycogen usage is unlikely to out last a 45 minute intensive resistance workout.

However depending on the initial body-fat percentage, the body will adapt to increasing its ability to use fat for energy, so an increase in cardiovascular exercise will not only benefit but is a must to continue a steady decrease in body fat.

Nutrition cannot be overlooked in this process either, as our body's' need a correct balance of carbohydrates (glucose), protein and fat to ensure there is enough of each for the body to run at its highest capabilities.

Without sufficient amounts of carbs, the body will simply not function efficiently and will use fat and muscle earlier in its energy usage processes. 

By maintaining a high fat intake, the body will be forced to use it, compared to storing it if a threat of malnutrition arises. 

An increased amount of protein is also crucial towards maintaining a high level of muscle mass. Without it, the body will quickly use protein (muscle) as energy, which will make gaining muscle size a slow and frustrating process. 

Fitness Rush Tips

Always warm muscle tissue up prior to exercise, with a steady cardiovascular warm up and dynamic stretch to ensure muscles are at their maximal training size and increase blood flow to the body.
For fat loss, steady state exercise for a sustainable time is advisable following an intensive resistance strength workout.
A good balance of macronutrients is important towards the bodies beneficial usage of its energy stores.
A good split might include (Depending on training target and workout intensity);
  • 40-50% Carbohydrates
  • 25-35% Protein
  • 20-30% Fat
Eat well, train hard and rest when you can for maximum growth and maximal results!