Initial results – Effects of Weight Reduction on Sleep and Alertness in Long-distance Truck and Bus Drivers

The recruitment of participants took longer than expected because the drivers took part in the study in their free time. A total of 113 men with the average age of 47 took part in the study, 83 of them were truck drivers and the rest were bus drivers. Most of them were employed.

84% of those who began the project took part in the tests one year after the beginning of the study and 71% took part in the tests at the end of the second year of the study. The participants were rather keen to take part in the counselling sessions as well as first and second year tests.

At the beginning of the study, the men's average weight was 106.9 kg and waist circumference 114 cm. A waist circumference of over 100 cm indicates significant abdominal obesity. The general target waist circumference for men is no more than 90 cm.

The drivers' average body mass index (BMI) was 33. A BMI of over 30 indicates obesity, while a normal BMI is under 25.

The effects of the lifestyle counselling

The effects of the one-year lifestyle counselling on weight, waist circumference and UKK walk test time have been presented in the table below.

The figures are the average of 95 men (47 men in the intervention group and 48 men in the control group).

  Intervention group     Control group    
  Beginning 12 months Difference Beginning 12 months Difference
Weight (kg) 106.9 103.5 -3.4 105.7 106.4 +0.7
Waist (cm) 114.4 109.7 -4.7 114.3 114.2 0
Walk time


17:34 16:51  -0:43 17:24 17:03  -0:21


After the one-year lifestyle counselling, the intervention group members had lost 3.5 kg on average and during the same year the control group members had gained a little over half a kilogram on average.

The waist circumference of the men in the intervention group had reduced by 4.5 cm on average, while the measurement remained unchanged in the control group. At an individual level there were also greater changes, both positive and negative. The best weight loss results were over 25 kg.

At the beginning, the UKK walk test time (2 km) was 17.5 minutes on average, which indicates a rather poor aerobic fitness level. After one year, both groups had improved their results.

The occurrence of metabolic syndrome was investigated by:

  • measuring the participants' waist circumference
  • checking their blood pressure
  • by taking blood tests to determine their HDL cholesterol, triglyceride and glucose levels.

If at least three of these five aspects are higher than the reference values, the person has metabolic syndrome which is a combination of several risk factors for cardiovascular diseases. The syndrome increases the risk of developing arterial diseases and type 2 diabetes.

At the beginning of the study, the syndrome occurred in nearly three quarters of the men. After a year of lifestyle counselling, the syndrome no longer occurred in nine men in the intervention group and two men in the control group.

During the second year after three months of counselling, the control group members lost a little over 4 kg on average and reduced their waist circumference by 4 cm. This is an encouraging result regarding the potential of short-term counselling.

At the end of the study, i.e. two years after the beginning of the project, the intervention group members weighed 3 kg less on average and their waist measurement had reduced by 4.5 cm since the beginning. The differences in the control group were 2.5 kg and a little over 4 cm.

Evaluation of implementation

Based on the preliminary results, it could be said that, despite the rather intensive counselling focused on various lifestyle aspects, the weight loss results achieved by the intervention group in a year was only moderate (less than half of the target).

The lifestyle change program required the drivers to make several changes in many lifestyle aspects and the post-counselling follow-up period of 9–12 months was short.

The participants' long workdays and irregular working hours were the biggest challenge as these aspects made it difficult to make lifestyle changes and turn them into daily routines.

Utilization of the study

Based on the project, training in healthy lifestyle choices has been prepared for professional drivers. This was proposed by the participants. This training has been approved by the Finnish Transport Safety Agency TraFi as further training for professional competence. The first course regarding the fitness, cardiac health and work alertness of professional drivers was held on 19 April 2012 at the UKK Institute.

Based on the project, a counselling program (including counselling and support material and training) will be planned for (occupational) health care personnel.

The counselling is designed for those who have irregular working hours and who are at risk of developing a cardiovascular disease. Three information leaflets have been prepared for this purpose and they deal with healthy nutrition, health-enhancing physical activity and sleep hygiene.



Katriina Kukkonen-Harjula, Senior Researcher




Last Modified: 27.11.2014


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