To OP:
Most people do not understand one aspect - cycles of 'Intensity' and 'relaxation'. When you do any workout with an objective of controlling b-sugar or weight; you must have a certain level of 'intensity' and should see sweat. That is the benchmark symptom for physical reaction. Some bodies take 20 min to get warmed up; some need 30min. So during warm up - take it easy, do not push yourself, try to be steady. Example is - walking for 30 or 40 min at moderate speed. After that take 2 or 3 minutes break (yes only 2 or 3 min break) and then raise the intensity to a level that you can comfortably do - jog or run steadily for another 30 to 40 min. Which means, exercise for 1 hour or beyond is very essential to see the results. Mornings are best for this type of exercise.
NOTE: if you are obese - DO NOT JOG or RUN. You simply damage your knees. I had this problem, so only walked to warm up. I did planks and resistance bands - this phase lasted for one full year. But results were very good weight dropped from 200lbs to 175lbs, but took a whole year. I repeat - during that year - what all I did - mild walking for 30min + 30 min of resistance bands + 20 min of planking (with breaks) - EVERYDAY. Because I was advised by a medical doc to prevent damage to my knees. I never gave up though.
Now coming to 'relaxation': It is equally important part of exercise. Best is to walk with group of friends - talking, laughing, arguing etc. OR walk your dog. OR recreational swimming. all are great - just that DO NOT exert at all. evenings are great for this type of activity. Sleep well after that.
Now, losing 25lbs over 1 year is not an achievement; most people do much better. But for my body - it took one whole year with complete focus and dedication. Morale was low, all my family members are T2D, no hope really; BUT I tried.
Now coming to the point raised by OP:
yes, I used to have higher BS after my exercise. Not sure why it was like that, but I remember that. But as my weight came down to 140lbs over the years (took 4 years which is very slow), I stopped checking my BS almost at home. Last time I did that is before and after X-mas just to keep myself under check - I went to a diagnostic center got complete blood work - all normal, perfectly fine. Now I run, jog and sprint or whatever as my BMI is around 23.5.
My slow rate of weight is connected to my family genes. Though I try hard to lose weight, body reacts like it wants more fat in it; just to make me look as any other member of my family - who are all obese. As I said, I tried hard and still doing to keep it under control. For now, I am under control, not sure when T2D will take over my body.
OP did not post details of weight, BMI, family-gene history of T2D etc. Those details are very imp here.
Best of luck.
PS: I am neither diabetic nor pre-D. Trying hard to avoid it. I am no medical doc; nor an expert in this area. Was addicted to French fries, pop-corn and Coke, but now eating healthy.