Always feeling cold and tired: the causes a blood test sees, and what an energy scan measures

In this article you will read why you can feel cold all the time and tired, what a blood test sees and what you can measure yourself. That matters, because sometimes there is something behind it that a doctor can find, and more often something everyday. Everyone is sitting in a T-shirt and you are wearing a cardigan. Your hands and feet are cold, you are tired before the day has begun, and you wonder whether the two belong together. Sometimes they do: being cold all the time and being tired is the combination in which an underactive thyroid and an iron deficiency announce themselves, and a blood test sees both. More often something more everyday is going on. BioProfile’s energy scan measures how much these complaints affect you, and gives you an indication of where you stand today in this area, as the first of the 11 health areas that the full scan assesses. This is not a diagnosis. It is insight, to see where you stand today. And to help you make better choices in your food and your lifestyle. What this scan does not do: measure your thyroid or your iron, or make a diagnosis. Only a doctor can do the latter, and only blood the former.

An underactive thyroid

You are tired, you feel cold, you gain weight: that is the list Thuisarts uses to describe an underactive thyroid, and the GP recognises it by a TSH that is too high in your blood.⁠¹ The full list is longer. The most common complaints in adults are fatigue, listlessness, poor tolerance of cold, weight gain, constipation, a changed voice and dry skin, and the severity runs from no complaints at all to life threatening. The condition itself is defined by the blood values and not by the complaints.⁠³

How often it occurs was measured in 25,862 visitors to a health fair in Colorado: 9.5 per cent had a raised TSH and 2.2 per cent a lowered one. The symptoms were more common in the people with an underactive thyroid, but each symptom on its own pointed to it only weakly. The researchers’ conclusion: anyone reporting several thyroid symptoms at once deserves a blood test.⁠² So feeling cold on its own is not a reason; feeling cold together with tiredness, weight and a sluggish bowel is.

Too little iron

The second cause blood sees is a shortage of iron. Worldwide it is one of the largest sources of disease burden, it affects children and women before the menopause most of all, and the symptoms can be there before the blood count shows anaemia.⁠⁴ Anaemia itself feels like being tired and weak, out of breath on exertion, dizzy, with a pounding heart and less colour in your face. It usually comes from too little iron, in women often from heavy periods, and over the age of 50 from blood loss in the bowel; the GP measures the haemoglobin, and anaemia means below 8.5 mmol/l in men and below 7.5 mmol/l in women.⁠^5,6 A shortage always has a cause, and the doctor looks for that as well.⁠⁴

When blood finds nothing

That is the usual outcome. If you have no other symptoms alongside the tiredness, a blood test almost never turns up a cause, Thuisarts says,⁠⁷ and in a Dutch cohort of 571 people who came to the GP with fatigue, a clear physical illness was found in 8 per cent within a year.⁠⁸

That leaves two everyday explanations. The first is a sleep debt you do not feel as a debt: people who slept six hours for fourteen nights performed, by the end, as though they had gone up to two nights without sleep, and felt barely sleepier.⁠⁹ The second is that your body makes less heat than the norm assumes. Researchers in Maastricht measured a lower resting metabolism in young women than the standard on which office temperatures are based, which explains why the same room is pleasant for one person and cold for another.⁠¹⁰ So cold and tired can also be two ordinary things at once.

What an energy scan measures

The energy scan asks five questions about the past two weeks: your energy through the day, energy dips, how much you lean on caffeine, becoming physically tired, and being too spent to do things. Each question is given points, the points are added up and converted into an energy score from 0 to 100, with the reading band it falls into. Higher is better. The questions are modelled on a validated fatigue scale written in Dutch; they are worded in house, not a copy, so the score is not a validated clinical score. What you get is a picture of how much fatigue you are carrying, and a baseline.

What an energy scan does not measure

A questionnaire cannot attribute fatigue to anything. An underactive thyroid, a shortage of iron, a poor sleep pattern and a low mood all read the same in it. So an energy scan does not make a diagnosis. Blood values are the layer that takes this from a picture of the burden to an explained picture, and those you ask a doctor for. Tiredness that lasts longer than a month, or that goes together with sweating at night, less appetite, shortness of breath or a lot of thirst, is a reason to see your GP.⁠⁷

What you do with your score

A score today is your baseline. Take the set of cold, tired, heavier and a sluggish bowel to your GP and ask for blood, because that set is the reason to take it.⁠² If the blood finds nothing, repeat the scan in two weeks, over the same questions, and work on your nights in the meantime: the debt you do not feel is the debt that costs you energy.⁠⁹ What a sleep test measures about that is in why you wake up tired.