HIIT workouts 4-5 times a week, safe or unsafe?

dfig619

So I recently started working out 5 days a week (Monday-Friday) Starting weight at about 220 (5' 6" Male)

I spend about 75-85% of my total time at the gym (1h 30m-1h 45m) doing cardio (Swimming, elliptical, and tread.)

3 weeks in and about about 207 (from 220) and have maxed my normal cardio work out (Elliptical) at the number 20 resistance.

So now im picking up HIIT training.
I'm not trying to gain to much muscle at the moment but I do free weights here and there. I want to get to about ~170/160, but not look flabby just fit. Im currently going by the MFP calorie intake which is about 1500 a day, and I'm pretty good at staying under or at that mark after working out.

My question is, will it be safe and healthy to do HIIT workouts 4-5 times a week? Is there any negative impact this can cause?

waster196

i lost around 100lbs doing this last year and it's safe, as long as you take a break when your body tells you you need it. also hiit workouts are just that - high intensity - make sure you feed your body enough or you'll be feeling weak and miserable.

laddyboy

because the afterburn effect last upto 48 hrs I would only do HIIT 3x per week and do strength 3x per week. Strength builds muscle and muscle burns fat. Don't skimp on the weight training.

joehempel

Your body will get used to it and you will NOT see the effects of it over time.

Switch it up...do weights one day cardio the next. But do high rep low weight to get some lean muscle and help build back what you lose doing cardio. You will gain muscle, so the scale will not show alot of loss, but you'll lose inches, which is way more important.

dfig619

because the afterburn effect last upto 48 hrs I would only do HIIT 3x per week and do strength 3x per week. Strength builds muscle and muscle burns fat. Don't skimp on the weight training.

That is true, I like to work with dumb bells to get my biceps toned and some chest press machines to also help tone that area, I'll keep that in mind when performing my workouts.

Thanks for the reply guys, if anyone else has any more tips I'm all ears!

SuperSexyDork

Your body will get used to it and you will NOT see the effects of it over time.

Switch it up...do weights one day cardio the next. But do high rep low weight to get some lean muscle and help build back what you lose doing cardio. You will gain muscle, so the scale will not show alot of loss, but you'll lose inches, which is way more important.

Low weight, high rep you say? -sigh-

OP, low weight, high rep is completely ineffective. As long as you don't train for hypertrophy you're not going to get bulky. Why not try a compound lift program like Stronglifts 5x5 or Starting Strength? Both are pretty excellent programs that give results. Google them, or I could give you links.

joehempel

Low weight, high rep you say? -sigh-

OP, low weight, high rep is completely ineffective. As long as you don't train for hypertrophy you're not going to get bulky.

That was the POINT, to NOT get bulky...it builds lean muscle, but it won't get you bulky LOL.

myofibril

My question is, will it be safe and healthy to do HIIT workouts 4-5 times a week? Is there any negative impact this can cause?

Yes, it inhibit recovery given the high intensity of the exercise. (I presume you are actually doing HIIT which means sprinting at maximal effort - most people are doing straight intervals when they profess to be doing HIIT...)

As such you should leave a day recovery between each HIIT session much like you would with a weights workout (which is why it is normally recommended that you do HIIT on the same day as your weights rather than leaving it for the next day.)

So you could try weights + HIIT one day, steady state cardio the next and so on.

Really if your goal is to lean out you would be just fine with good diet, weights 3 times a week with a couple of steady state cardio sessions thrown in (although not strictly necessary.)

SuperSexyDork

Low weight, high rep you say? -sigh-

OP, low weight, high rep is completely ineffective. As long as you don't train for hypertrophy you're not going to get bulky.

That was the POINT, to NOT get bulky...it builds lean muscle, but it won't get you bulky LOL.

I don't think you got my point.

Why not read this article and maybe you will.

http://www.builtlean.com/2012/07/19/high-reps-vs-low-reps/

Particularly this part:

One study from the University of Alabama in Birmingham showed that dieters who lifted heavy weights lost the same amount of weight as dieters who did just cardio, but all the weight lost by the weight lifters was fat while the cardio queens lost a lot of muscle along with some fat. The common belief is that high reps magically get rid of fat. While high reps with light weight to fatigue can create a muscular response, it does not necessarily remove fat better than low reps with heavy weight.

While more studies are needed to compare the fat loss effects of high reps vs. low reps, substantial evidence is mounting that it’s not necessarily the amount of weight that is used, or the number of repetitions that helps burn the most fat, but the intensity of the workout. The goal is to create muscular failure with less rest between exercises, which can have powerful hormonal, metabolic, and calorie burn effects (See: afterburn effect). In addition, for fat loss, proper nutrition will have a MUCH greater impact on fat loss than the specific rep range, or even workout.

and this:

There is a common misconception that lifting heavier weights automatically helps you build muscle. That’s not the case at all. In fact, how much you eat in combination with the overall volume and intensity of the workout and how it becomes more challenging over time will make the difference, not necessarily the weight/reps. If you eat relatively less calories than you burn, you can lift very, very heavy weight and most likely not gain an ounce of muscle mass... In a calorie deficit, increases in strength are likely due to neuromuscular adaptation and not increases in muscle mass.

and this part especially:

Strength – Under 6 reps (0-15% of exercise volume)

Hypertrophy – 6-15 reps (70-85% of exercise volume)

Endurance – 15+ reps (15% of exercise volume)

As stated earlier, the intensity of the workout is more important than the specific rep ranges for fat loss, but the following is a smart approach that combines what I consider the “sweet spot” of the 6-15 reps, which can further be broken down into 6-10 and 10-15. For less advanced lifters and the general population, those ranges can be changed slightly to 8-12, and 12-15.

There a couple very compelling benefits of the 6-15 rep range. First, you are getting significant muscle stimulation with much less chance of injury than lifting very heavy weights for low reps (under 6 reps). Second, it takes less time to workout than using 15+ reps all the time, which does not offer much added benefit. If you are a beginner, I recommend against using under 12 reps. If you don’t want to push yourself with low reps, there isn’t any need to go below 6 reps, or even below 10 reps if you are older, or fear getting injured. Lifting in multiple rep ranges will help stimulate a maximum amount of muscle fibers to help burn fat and improve overall fitness.

edit: forgot to close a quote bracket.