“I lift weights for two hours and do 30 minutes of HIIT every day,” wrote one Muscle Evo reader.
“Are there any negative issues that might result? Will I lose muscle gains by doing this?”
There are indeed a few “negative issues” with your current training program.
Firstly, lifting weights for two hours every day comes to 14 hours of training a week.
That’s way more than most people need, or can even recover from.
I know guys on the juice who are doing less than that.
In the majority of cases, 3-5 hours of strength training per week is plenty. That’s more than enough to get the job done.
Second, it says to me that you’re not entirely clear on what you’re trying to achieve.
Do you want to build muscle? Lose fat? Improve your conditioning?
It’s my opinion that you’re better off having one clear goal (i.e. fat loss or muscle growth), and focusing on that goal to the exclusion of everything else.
Trying to go in several different directions all at the same time almost always leads to a frustrating lack of progress.
If your main goal is to build muscle, some light cardio two or three times a week for 20-30 minutes is plenty. And by light, I’m talking about something that gets your heart rate up to around 70% of its maximum. A brisk walk in the fresh air first thing in the morning will do the job just fine.
You certainly don’t need to do HIIT every day.
Third, HIIT is a very demanding form of training.
Doing HIIT every day on top of daily strength training (which, if you’re doing it properly, is itself a form of intense intermittent exercise) will seriously impair your ability to recover and grow.
Here’s what Greyskull Barbell Club owner John Sheaffer has to say on the subject:
“Once the base of strength is established the decision is then made as to what is appropriate in terms of ‘conditioning’ work. If something is going to be added to a program then one must understand that total recovery ability will be spread thinner than it previously had been.
“If someone was formerly lifting weights three days per week and resting on the other days, then they are in for a rude awakening if they attempt to add three high intensity conditioning workouts on the days in between. Often times, the simple addition of a single stress outside of a regimented program can bring progress in the program to a halt, or at the least slow it down considerably.”
Let me repeat that last sentence:
Often times, the simple addition of a single stress outside of a regimented program can bring progress in the program to a halt, or at the least slow it down considerably.
In other words, doing HIIT every day alongside a training program designed to make your muscles bigger and stronger has the potential to put the brakes on muscle growth.
Martin Berkhan, high priest of intermittent fasting, makes a similar point here:
“Even though you burn more calories in less than half the amount of time compared to, for example, brisk walking, HIIT is very draining on the central nervous system. In stark contrast to lower intensity cardio, which you can do for a much longer time, with much greater frequency. For someone interested in fat loss and strength maintenance, and not metabolic conditioning primarily, including HIIT too frequently is playing with fire.”
Elliot Hulse talks about some of the problems he encountered when trying to combine interval training with bodybuilding-style workouts in the video below:
Back in the day when I was an interval training “fundamentalist,” the only cardio I did was 20 minutes of HIIT first thing in the morning three times a week. I considered anything other than HIIT as nothing more than a wasted opportunity for progress.
Given the superiority of HIIT over steady-state cardio, I thought to myself, why spend time doing something that takes longer and is less effective?
What I learned the hard way is that interval training is very tough on the body, especially if you combine it with three days a week of heavy strength training and a calorie-restricted diet.
While HIIT helped me drop fat as well as maintain a reasonably high level of conditioning, I noticed that it had an adverse effect on my strength levels in the gym. And I would often feel burned out, tired and irritable.
There’s also research to show that doing HIIT immediately after lifting weights can interfere with some of the molecular processes involved in muscle growth .
In fact, the interference effect was even greater than previously seen in an earlier study that combined resistance and endurance training (30 minutes of cycling at 80% of maximum heart rate) .
Granted, the study only looked at the short-term (3 hours after training) molecular response to resistance training, rather than measuring protein synthesis or muscle growth directly. So we don’t know the extent to which your muscular gains will be compromised after several months of training.
In addition, both the HIIT and resistance workouts also involved the legs. You won’t see the same effect doing HIIT after an upper-body workout.
Even so, lifting weights and doing HIIT every day is not a great idea. If you want to do HIIT while you focus on building muscle, limit it to 1 or 2 short sessions a week.
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