The science behind steady state cardio
Type: low intensity, long duration
Good for: fat burn, stress management, aerobic fitness
Steady-state or low-intensity training (LISS) is the bread and butter of cardiovascular health and increasing endurance fitness levels. Given it’s generally performed at about 65 per cent of your maximum heart rate (think jogging or a fast-paced power walk) for upward of 45 to 60 minutes, it has the added benefit of burning fat rather than carbs as its primary source of fuel. It’s low stress, and often low impact, perfect for building a beginner’s fitness base, and can help manage the fat-storing stress hormone cortisol after a busy nine-to-five slog.
LISS relies on your aerobic energy system, with aerobic literally meaning ‘with oxygen’. Because lower-intensity exercises have greater access to oxygen, fats, carbohydrates and even proteins for synthesising ATP for fuel, it can produce practically unlimited energy for long periods of time – just not very quickly, meaning sprinting is out. What it is good for is improving cardiovascular endurance, or how much oxygen is diffused across your muscles and how much energy it takes to achieve this – i.e. your VO2-max or the highest heart rate you can maintain.
“When we improve our VO2-max, we can use more oxygen during exercise, which means more of it gets to the muscles and we can produce more ATP for energy,” explains exercise scientist Johann Ruys.
“If we then also build up our tolerance to lactate, or ‘muscle burn’, we can maintain a higher percentage of our VO2-max for longer durations without burning out or suffering from severe pain from acid accumulation in the blood and muscles.”
In other words, steady-state training strengthens your heart muscle and increases your ability to produce ATP for energy, allowing you to run harder for farther.
Unlike resistance training, recovery time required post-LISS is limited – you can return safely within hours. A recent study of elite athletes, published in Sports Medicine journal, recommended just three hours of recovery after endurance training.
“Steady-state cardio doesn’t place too much strain on the muscles, therefore they don’t need time to repair like they do with heavy weights,” says exercise physiologist Leah Rowan.
That said, Rowan suggests limiting LISS to a maximum of 60 minutes a day to guard against overtraining.
Steady-state cardio is not the ideal method for improving fitness or shredding fat if you are time poor, with plateaus quick to come by and greater distance and hours required to continue improving. Steady-state cardio’s lower work rate means it needs to be substantiated for upward of 45 minutes to adequately dip into fat stores, and you only burn calories (and so fat) while you perform it – in contrast to the ‘afterburn’ native to higher intensities.
Longer durations of exercise also tend to wreak havoc on your joints, so injuries, especially among runners, are common. To mitigate, consider at least three sessions per week spent performing low-impact versions such as swimming.
The type of cardiovascular training selected should also be considered if you are chasing booty gains: a study published in the Journal of Applied Physiology found that 10 weeks of combined resistance and cardio training resulted in strength gains being halved when compared to weightlifting alone – although fat loss was far greater. To continue hitting PBs while still remaining relatively lean, opt for steady-state forms such as cycling that still encourage the range of motion and muscle activation similar to weight training. A 2009 study published in the Journal of Strength & Conditioning Research found that uphill walking produced far greater reductions in strength than those participants who hit the bike.
For fat loss, consider performing LISS on an empty stomach. According to a recent study published in Sports Medicine, exercising in a fasted or glycogen-depleted state creates adaptations in the body’s fat-oxidising abilities, meaning your body will turn to increased fat for fuel.
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