How to end up on the podium after running a 6-days-run with type 1 diabetes mellitus - A case study and literature review

BACKGROUND

An increasing number of people living with type 1 diabetes mellitus (T1DM) are pushing their physical limits to compete at the sport's highest level. Muscle, liver, and glycogen metabolism can be normal in athletes with diabetes with good glucose management, and modifications to insulin dose and nutrition can facilitate exercise performance.

CASE PRESENTATION

We report on a 66-year-old runner with insulin-dependent T1DM. He has run over 90 marathons and ultra-marathons. Thanks to an insulin pump and continuous glucose monitoring, he has completed forty-eight 24-hour runs with an average performance of 133.8 km. Over the years, the runner increased his monthly running volume significantly and decreased his glycated Hemoglobin type A1C (hba1c) levels. Meanwhile, a significant association between monthly running kilometers and hba1c levels could be shown. At the age of 66 years, he finished his sixth 6-day-run in third place overall by covering a total distance of 467.424 km.

CONCLUSIONS

These findings show that it is possible to participate in ultra-endurance events while suffering from T1DM without glucose derailing. With a good understanding of the disease and its impact on an individual's body, we can curtail the preparation and execution phases of ultra-endurance events to allow athletes to compete with minimal risk.

Temperature and barometric pressure are related to running speed and pacing of the fastest runners in the 'Berlin Marathon'

OBJECTIVE

The influence of environmental conditions, such as temperature, barometric pressure, humidity, precipitation, sunshine and cloud cover on marathon running has been widely investigated. However, the influence of such conditions on the pacing of elite marathoners has not been considered yet. The present study aimed to investigate whether environmental conditions are related to the running speed and pacing of the fastest marathoners competing in the fastest racecourse in the world, the 'Berlin Marathon'.

SUBJECTS AND METHODS

A total of 668,735 finishers (520,715 men and 148,020 women) competing between 1999 and 2019 in the 'Berlin Marathon' were analyzed by comparing elite and recreational runners. The associations between time-adjusted averages of the environmental conditions, the race times and running speeds were investigated. The runners were divided into performance groups consisting of recreational (all runners) and elite runners (the top 100, the top 10 and the top 3) which were separately analyzed for male and female participants.

RESULTS

During race days, the temperature increased while humidity decreased showing a strong negative correlation between the two variables. For all runners, the average running speed through the race showed a strong negative correlation with temperature and a strong positive correlation with the level of humidity. Faster runners experienced lower temperatures and higher humidity levels than slower runners. When the performance groups were analyzed, temperature and humidity remained correlated to a similar extent for the top 100 but dropped dramatically for the top 10 and top 3, suggesting a weaker influence. In addition, barometric pressure showed a positive correlation with running speed in the top 100 and top 3 groups.

CONCLUSIONS

Temperatures increased during race days while humidity decreased and both variables were negatively and significantly correlated. Faster runners experienced lower temperatures and higher humidity levels, while slower runners experienced higher temperatures and lower humidity levels which had a stronger negative impact on running speeds. Running speed was also significantly and positively correlated with barometric pressure in elite runners.

Nucleation particles in diesel exhaust: composition inferred from in situ mass spectrometric analysis

Mass spectrometric measurements of size and composition of diesel exhaust particles have been performed under various conditions: chassis dynamometer tests, field measurements near a German motorway, and individual car chasing. Nucleation particles consisting of volatile sulfate and organic material could be detected both at the chassis dynamometer test facility and during individual car chasing. We found evidence that if nucleation occurs, sulfuric acid/water is the nucleating agent. Low-volatile organics species condense only on the preexisting sulfuric acid/water clusters. Nucleation was found to depend strongly on various parameters such as exhaust dilution conditions, fuel sulfur content, and engine load. The latter determines the fraction of the fuel sulfur that is converted to sulfuric acid. The organic compounds (volatile and low-volatile) condense only on preexisting particles, such as both sulfuric acid nucleation particles and larger accumulation mode soot particles. On the latter, sulfuric acid also condenses, if the conditions for nucleation are not given. The overall ratio of sulfate to organic (volatile and low-volatile) is also strongly dependent on the engine load. It was found that the production of nucleation particles even at high engine load can be suppressed by using low-sulfur fuel.