I am Dr. Arun and will be helping you today.
I am sorry that your question was unanswered for long.
A control of sugar is achieved by mainly following;
2) Physical activity
3) Medications; a) oral b) insulin.
In an individual a fixed combination of above works. Even a tiny variation may lead to significant variation.
These three variable if are not likely to be responsible for the rise of blood sugar, following may be the factors;
1) Temperatures variations and extreme fluctuations.
4) Medications, herbs, supplements.
5) Hormonal; episodic thyroid or adrenal hormonal issue may give rise to increase in blood sugar though blood work may not be able to detect them (as the hormonal fluctuations are in the highest range of normal).
Please feel free for your follow up questions.
I would be happy to assist you further, if you need any more information.
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