HIIT

[shews]

About to start the body coach plan and wondered how a HIIT work out will affect my levels.
When I exercise I avoid eating before by allowing myself to run a little high- say 10-12 but often crash afterwards anyway.
Also plan. To exercise before 6am on an empty stomach and have a carb breakfast.
Thanks
Sally

 

[Jeztrob]

Hi Sally,

My experience with any form of exercise is as follows:
If I go 'all-out' my BS rises - the body thinks it needs sugar and so releases it into the blood-stream.
If I go for a walk (1 hr +) then I find that my BS levels drop as I'd expect - I also find the same if I'm cleaning the house! This is because the body isn't in 'OMG - you need sugar!' mode and so uses the available resources it has
After the exercise the body stops 'needing' the sugar and so this might be why you crash...but I don't know I'm afraid...

I have a limited HIIT routine that I do most evenings at home after work and before dinner - it lasts about 30 mins (press-ups / plank / sit-ups / standing twists / lunges or variations thereof) but I find that this routine alters my BS levels depending on how hard I go at it...the harder I go the higher the levels post-exercise.

If you are training with a Personal Trainer I'd tell them before you start and keep a can of Coke nearby just in case you get that crash after the exercise.

As with all new activities you are going to have to see how your body copes (!) but I'd say go for it - the only thing that its done for me is to make me fitter!

Jez
Age 49
Diagnosed October 1968

 

[tim2000s]

Yup, as @Jeztrob mentions, HIIT is an anaerobic activity and as a result, the body releases glucose into the blood. It then typically sucks it back afterwards, but I would check your glucose before, during and afterwards for a few hours to see what the pattern is. Many of us when engaging in HIIT find that we need insulin on board to maintain flat levels.

 

[shews]

Really helpful thanks

 

[qe5rt]

Worth a read

Results
Five patients did not complete the study and were therefore excluded from analysis: this left 12 HIIT and 11 control patients for the intention-to-treat analysis. Compared with controls, HIIT improved cardiac structure (left ventricular wall mass 104 ± 17 g to 116 ± 20 g vs 107 ± 25 g to 105 ± 25 g, p < 0.05) and systolic function (stroke volume 76 ± 16 ml to 87 ± 19 ml vs 79 ± 14 ml to 75 ± 15 ml, p < 0.01). Early diastolic filling rates increased (241 ± 84 ml/s to 299 ± 89 ml/s vs 250 ± 44 ml/s to 251 ± 47 ml/s, p < 0.05) and peak torsion decreased (8.1 ± 1.8° to 6.9 ± 1.6° vs 7.1 ± 2.2° to 7.6 ± 1.9°, p < 0.05) in the treatment group. Following HIIT, there was a 39% relative reduction in liver fat (p < 0.05) and a reduction in HbA1c (7.1 ± 1.0% [54.5 mmol/mol] to 6.8 ± 0.9% [51.3 mmol/mol] vs 7.2 ± 0.5% [54.9 mmol/mol] to 7.4 ± 0.7% [57.0 mmol/mol],p < 0.05). Changes in liver fat correlated with changes in HbA1c (r = 0.70, p < 0.000) and 2 h glucose (r = 0.57, p < 0.004). No adverse events were recorded.

Conclusions/interpretation
This is the first study to demonstrate improvements in cardiac structure and function, along with the greatest reduction in liver fat, to be recorded following an exercise intervention in type 2 diabetes. HIIT should be considered by clinical care teams as a therapy to improve cardiometabolic risk in patients with type 2 diabetes.

and also

Diabetes researchers are particularly interested in the positive effect that HIIT appears to have on blood glucose levels and insulin sensitivity. A recent review of eight small studies of groups of people with type 1 and type 2 diabetes found brief HIIT sessions improved blood glucose for 1 to 3 days post-exercise. The other finding showed how HIIT was less likely to cause hypoglycaemia both during and immediately after exercise.3

There are different interpretations of HIIT and not all of them are correct in my opinion. I would honestly stay away from any form of resistance effort and HIIT since there's the issue of posture when lifting anything. Since HIIT is based on a % of your maximum aerobic power any exercises that raises your heart rate will do just fine without much risk of bad form. I'm talking about running, jogging, sprinting, cycling, home trainer, ... Generally speaking you'll need to reach more than 70% of your maximum aerobic power. Calculating that would require a MAP test which isn't really required unless you're extremely serious or it's relevant for a study like the ones i quoted above. Just get your heart pumping with either calmer periods or rest periods. Most HIIT sessions in studies or generally performed are between 4-20 minutes. The optimal combination is yet to be determined and is somewhat dependent on your personal fitness level. Also the peak you're going to get on the high intensity bout will determine the total amount of minutes you can achieve. I used to do a 30 second jog and then a 20 second sprint (= 1 cycle) after 5-6 cycles i was completely finished physically. Don't be shy experimenting a bit with different combinations and remember that it can have an effect 1-3 days after a session.