Cardio or resistance first for fat loss?

Adapting training programmes to include both cardiovascular and resistance exercise to maximise fat loss is undoubtedly beneficial.

School Of Personal Training Posted Jul 08, 2015 Future Fit Training

One of the common questions is which you should do first if you’re doing both in the same session.

This article will describe how to amalgamate the two modalities primarily for proficient fat loss, rather than strength and muscle building. However, still bear in mind the importance of muscle mass in the fat burning process. 

The best way to order workouts may ultimately still be to perform cardio and resistance training on different days or different times of day. Realistically, this is not always possible, so integrated workouts such as circuit training or cardioacceleration can be beneficial here.

Cardioacceleration is the inclusion of anaerobic cardio activity during rest periods between sets. Davis WJ et al, 2008 evaluated the effects on muscular strength, cardiovascular endurance, flexibility and body composition by comparing resistance training followed by aerobic training, then resistance training with integrated cardio; i.e. cardioacceleration.  The integrated workouts produced higher results in strength, endurance and flexibility with a subsequent decline in body fat. 

However, if the preference is still to perform concurrent training we must analyse the pros and con' of the pre- or post- resistance cardio training option.

The possible benefits of pre-resistance cardio, depends on the modality, intensity and subsequent muscle groups to be trained that day.

Both training modalities cause hormones and enzymes to be released, resulting in metabolic responses.  By activating the enzyme mTOR, resistance training stimulates protein synthesis and muscle building, whereas endurance cardio burns fat by activating the enzyme AMPK.  However, this can unfortunately cause a reduction in mTOR signalling and potentially inhibit muscular growth.  This is due to the two enzymes being released simultaneously, causing a conflict as the two then become antagonistic forces.

If the cardio phase is implemented first then this may not be a problem as AMPK activation only endures for approximately 60 minutes post-exercise (Dreyer, H 2006), therefore the activation of this prior to resistance training should ensure that synchronisation of enzymes does not continue during post-workout protein synthesis, allowing fat burning and muscle building to be promoted.

Cadore, E et al, 2012 examined the hormonal responses to exercise orders.  Participants completed a strength session to include 4 sets of 8 repetitions at 75% of 1RM and an aerobic session consisting of 30 minutes of moderate intensity, 75% of maximal heart rate on a cycle ergometer. These workouts were completed in opposite orders with hormone levels measured pre-, during and post-exercise.

In my previous articles I have described the importance of testosterone and cortisol and it's potential to aid or inhibit fat loss. Regardless of exercise order, testosterone and cortisol levels will inevitably rise. However pre-session cardio caused a continual rise in testosterone rise throughout the training session, the opposite of the reverse order.

With these points in mind it seems that cardio performed before resistance work may elicit more of the desired response.

The mode of cardio performed must also be considered. For example, if we compare endurance running to cycling, the latter is significantly better for achieving hypertrophy when combined with resistance training. The greater demand for multi-joint activation here, mimics exercises that are particularly beneficial to metabolic training, such as squats (Gergley, JC 2009).

As previously discussed, another consideration is the total duration of the cardio performed. It could be argued that the longer the cardio session, the greater the detriment to the hypertrophy goal and the greater the increase in catabolism. However, the dynamic of the cardio can be chosen to favour sports specific conditioning (Tremblay, 2014).  Short intervals of high intensity have been shown to have no negative impact on resistance training (Gergley, JC 2009).  On the contrary, the high velocity contractions activate the fast twitch muscle fibres, increase EPOC and support fat loss. Therefore, with these factors in mind a strong case can be built for pre-session cardio in concurrent training.

Bodybuilders in particular have often used post resistance training cardio as their order of choice for fat loss. The hypothesis here is that during resistance training the muscles are not fatigued and are able to deplete their glycogen stores, this then allows more fat to be burned during the cardio phase. The fear is that by performing the cardio phase first, blood sugar will still be the primary fuel and the fat stores will not be utilised. This then leaves the anaerobic resistance phase of your session relying on those fats for energy.

With the preferred fuel being glycogen during short muscle contractions (Griffin, J 2015) fat is not as efficient a fuel for weight training. This may cause muscular gains and ultimately fat loss to suffer. So, with this in mind should we reserve the cardio phase until resistance training has been completed?

In my opinion this greatly depends on the person, their genetics, their goal and the design of their resistance program. Whichever option is preferred, you will burn more calories, increase muscle, increase metabolism and create a complimentary concurrent session by incorporating HIIT rather than endurance training.

Multiple modalities being trained on the same day can confuse the body as to how it should respond, thus leading to detrimental adaptations and the Interference Phenomenon.

However, cardiovascular exercise followed by resistance training seems to hold the most positives. If there is a fear of premature fatigue then different muscle groups could be worked during the two training modalities; for example avoiding excessive rowing if the upper body is then to be trained. On the other hand, the decision about the intensity of the cardiovascular exercise completed prior to the strength workout can be based exclusively on the goals of the client for that workout. With the goal here being fat loss, drive your workout for that purpose by incorporating these handy tips to fuel your furnace and reach your goals.