Excessive thirst and frequent urination: check your blood sugar

Why thirst and frequent urination stand out together

A blood sugar that is structurally too high eventually ends up in the urine through the kidneys. Glucose attracts water, so anyone passing sugar also loses extra fluid. You notice that as larger volumes, more trips to the toilet and waking up during the night.

The body tries to compensate for that fluid loss with thirst, which creates the circle many people recognise: drinking a lot, passing a lot, and still having a dry mouth. Because it develops gradually, it is often only noticed when someone else mentions it.

Other complaints regularly come along with it:

• persistent fatigue
• blurred vision that varies from day to day
• losing weight without trying
• itching or recurring fungal infections
• small wounds that heal more slowly than you are used to

At the same time, this combination is not proof of anything. Frequent urination can also be caused by a bladder infection, an enlarged prostate, water tablets, plenty of coffee or tea, or simply the habit of drinking a lot. A blood test is the only way to confirm your blood sugar as the cause or to move it out of the picture.

Glucose or HbA1c: what does each measure?

A fasting glucose measures how much sugar is in your blood at that moment, after a period without food. It is a snapshot, and it moves with what you ate the evening before, how you slept, whether you are unwell and how much strain you were under.

That is exactly why the laboratory asks you to come fasting: without that agreement, results cannot be compared properly. Drinking water is fine, and sensible too, because a well-filled vein makes the draw easier.

HbA1c looks much further back. Sugar in the blood slowly attaches to haemoglobin, the protein in your red blood cells. Because red blood cells last roughly two to three months, HbA1c is a measure of the average level over that period.

One day of heavy eating does not shift it, and you do not need to fast for it. The drawback of an average is that you do not see the swings across the day, and that it responds slowly: a change in your lifestyle only becomes visible after months.

Prediabetes: the stage where most can still be gained

Between a healthy blood sugar and type 2 diabetes lies an in-between stage known as prediabetes. Blood sugar is then structurally higher than desirable, without the criteria for diabetes being met. The difficult part is that this stage usually causes no complaints.

Thirst and frequent urination generally arrive once values climb further, so anyone waiting for symptoms is often already a step beyond. Many people discover it by chance, for example during a medical check or a test taken for another reason.

That quiet stage is worth knowing about, because this is the period in which lifestyle has the greatest effect and in which some people can delay or prevent the progression to type 2 diabetes.

Who is at greater risk?

The risk of disturbed blood sugar regulation is greater with:

• type 2 diabetes in the family
• excess weight, and especially fat around the waist
• little physical activity
• getting older
• gestational diabetes in the past or polycystic ovary syndrome
• high blood pressure or an unfavourable cholesterol profile
• a South Asian, Turkish, Moroccan or Afro-Caribbean background, sometimes at a younger age
• long-term use of certain medication, for example corticosteroids

If you recognise several of these points, measuring periodically makes more sense than waiting for complaints to appear.

What lifestyle does, and what it does not do

Physical activity is one of the few measures with a directly measurable effect: after exertion, muscles take up sugar without needing much insulin. Most people find a half-hour walk after the main meal easier to sustain than a strict diet.

It also helps to replace sugary drinks, to eat more fibre and to pay attention to your sleep, because sleep deprivation affects blood sugar regulation unfavourably.

What lifestyle does not do is solve everything. In type 1 diabetes insulin is essential and lifestyle is not an alternative. In type 2 as well, a point can come where medication is needed, and that is not a personal failure. If you already take medicines, never adjust them yourself on the basis of a blood result.

When a blood test is not the answer

There are situations in which you should not wait for a result. Contact your GP or the out-of-hours service the same day with:

• extreme thirst combined with rapid weight loss
• nausea, vomiting or abdominal pain
• deep or rapid breathing
• drowsiness or confusion

That picture can indicate a seriously deranged blood sugar and should be assessed the same day. With children, teenagers and young adults whose complaints develop within a few weeks, the GP belongs in the picture too, because type 1 diabetes can progress quickly.

And if frequent urination is the only issue, without thirst and without other complaints, the cause lies more often in the bladder or prostate than in your blood sugar. A normal blood sugar result does not rule those causes out, so have urinary complaints assessed separately.

Having your blood sugar measured at Bloodworks

At Bloodworks you have your blood sugar tested without a referral, at one of the more than 750 affiliated collection points across the Netherlands. The Blood sugar package combines a fasting glucose with HbA1c, so you have both the moment and the average of recent months in view.

Every result is reviewed by a doctor and reaches you as a personal PDF report, typically within 2 working days. It explains what your values mean in your situation and whether contacting your GP is sensible. If you want a broader look, for example because your cholesterol also deserves attention, you can include that in the same blood draw.