Hypoglycemia while driving, at school and at work

Before you set off in the car, your blood glucose must be above 90 mg/dL (5.0 mmol/L) [1]. This value gives you a safety margin, because blood glucose can sometimes fall very quickly while you drive [1]. If you set off with a lower blood glucose, hypoglycemia can occur on about one in four journeys [1]. You should know that blood glucose can start to fall in the very first minutes of the journey, so pay attention right from the start [1].

If your blood glucose is between 70 and 90 mg/dL (3.9–5.0 mmol/L), eat carbohydrates before you set off [2] [3] [4]. If you use a sensor, also look at the trend arrow, which shows whether your blood glucose is rising or falling [5]. A downward arrow means that blood glucose may drop below 70 mg/dL (3.9 mmol/L) during the journey, even if the current value looks good [1] [4] [5]. On long journeys you should test your blood glucose again at least every two hours, as the figure below shows [2].

You must stop the car as soon as possible in a safe place [2] [4]. Then switch off the engine, take the key out of the ignition and, if you can, move to the passenger seat. This makes it clear to anyone that you are no longer driving. Treating hypoglycemia starts with 15 g of fast-acting carbohydrates [6]. After 15 minutes you should test your blood glucose again [6].

Hypoglycemia affects the way you drive even before you clearly feel it [3]. Many drivers do not realize it in time and treat hypoglycemia only after their blood glucose has fallen quite a lot [3]. That is why you should not try to reach the next gas station. Glucose must be within your reach, not in the trunk [2].

You must wait at least 45 minutes after your blood glucose, tested with a glucometer, has returned to normal, not from the moment you ate [2]. Blood glucose can return fairly quickly after hypoglycemia is treated, but the brain needs more time to work normally again [7]. Reaction time can stay slower even for more than an hour after blood glucose has returned to normal [7].

The return of your blood glucose to above 90 mg/dL (5.0 mmol/L) must be checked with a glucometer, even if you use a sensor [1] [4]. Unfortunately, many drivers set off too soon after treating hypoglycemia [2]. After severe hypoglycemia, the break from driving is longer, and in many countries the law explicitly requires this break [2] [4]. It is best to decide together with your doctor when you can drive again.

Keep within reach in the car glucose for at least two treatments of hypoglycemia, your glucometer with test strips and your phone with the sensor alarms on [2] [4]. Keep two rounds of treatment, because sometimes blood glucose stays below 70 mg/dL (3.9 mmol/L) after the first dose of carbohydrates and you will need to repeat the treatment [6]. Most drivers treated with insulin keep carbohydrates in the car, but many of the other safety rules are followed less often than this one [2].

Add water, a medical ID card showing that you have diabetes and a snack with slowly absorbed carbohydrates, fat and protein [2] [4]. Do not leave insulin in the car, because in a vehicle heated by the sun the heat can damage it [8]. Check the expiry dates of your glucose and of your glucometer test strips once a month.

Special attention is needed in jobs where hypoglycemia can put you or others in immediate danger. Examples are professional driving, working at heights or with machinery, emergency services and aviation. The rules differ from one country to another, and for driving they also differ by license category [2] [9]. Some jobs are still restricted, but more and more are opening up, including that of airline pilot [9].

What matters is how you prevent and treat your hypoglycemia, not the diagnosis itself. A diabetes diagnosis does not decide independently whether you can drive safely [4]. Patients with type 1 diabetes can hold any job for which they are qualified and which they can do safely [9]. In these jobs, a sensor with alarms, meal breaks and a written plan agreed with your doctor are essential.

Not always. In many workplaces disclosure is not mandatory, but some have their own safety rules, and laws differ between countries [9]. Your workplace should offer you reasonable adjustments, such as access to insulin, the possibility to test your blood glucose and time to manage your diabetes [9]. This also includes time for your sensor or pump [10].

Most adults with diabetes face prejudice related to diabetes, and some even face discrimination, including at work [11]. That is why a middle way is to tell 1–2 trusted colleagues what hypoglycemia looks like in you and where you keep your glucose and glucagon [6]. The workplace first aid kit must contain glucose [6]. You can keep your glucagon at work in a place that trained colleagues know about [6].

Set your meal breaks at times that are as fixed as possible, matched to your insulin schedule. If your break is delayed, do not give your mealtime insulin dose early, but when the food is in front of you, as the page on meals and hypoglycemia explains. Keep a snack with carbohydrates in your desk drawer for the days when you cannot take your meal break.

Preventing hypoglycemia also matters for your work. After common hypoglycemic episodes that are not severe, many employees work more slowly [12]. Almost one in five employees who have hypoglycemia at work then miss work, on average for more than a working day [12]. If you work night shifts, the timing of your basal insulin dose and of your meals must be agreed with your doctor, because your insulin needs change over the day.

Teachers need to know what hypoglycemia looks like in that student, how it is treated and whom to notify. For this, every student with diabetes needs a written school care plan approved by the doctor [13] [14]. The plan must include the insulin doses, the blood glucose targets, the steps to take during hypoglycemia and the people trained to help when needed [13] [14]. The student should be able to test blood glucose, eat and drink in class, and glucagon is kept in all the places the student goes [13] [14].

In young children, hypoglycemia often shows in behavior, through irritability, restlessness, unusual quietness or crying spells, also described on the page about signs of hypoglycemia [15]. A student with hypoglycemia is never sent anywhere alone, because their judgment may be impaired [14] [15]. The student's sensor and pump, with their alarms, are also used at school, and school staff help the student use them [10] [16].

Anyone who has been trained in advance can help you. At school, this can be teachers, the school nurse and other trained staff, and at work, close colleagues [13] [14]. No medical training is needed to give glucose to a conscious patient or glucagon to one who cannot swallow [6].

Training is short and done in advance. You need to show where you keep your glucose and glucagon and explain what the people around you should do during severe hypoglycemia. If you cannot swallow, do not respond or have seizures, the people around you give you nothing by mouth, give you glucagon and immediately call emergency services [6].

Before you start, it is a good idea to test your blood glucose and make sure it is within your target range. Your glucose must be within reach. The sensor stays on, with the alarms set to vibrate. At school, the written plan must allow blood glucose testing, eating and a break during the exam, without penalty [13] [14].

The stress of an exam can lead both to hypoglycemia and to high blood glucose [14]. Hypoglycemia lowers precisely the concentration, short-term memory and thinking ability you need so much in an exam [15]. If you feel hypoglycemia, you must treat it immediately, even if you lose time, because otherwise you may think more slowly for a good part of the exam [7]. Do not use insulin to correct a high blood glucose caused by nerves right before going into an exam.