Separate studies show having sex and marathon running safe for people with type 1 diabetes
· Sex is safe in type 1 diabetes, shows small study using continuous glucose monitoring devices
Note this is an early release from the Annual Meeting of the European Association for the Study of Diabetes [EASD] from the Media Center
New research to be presented at the Annual Meeting of The European Association for the Study of Diabetes (EASD) in Milan, Italy (Sept 28 – Oct 2)
shows, with the use of continuous glucose monitoring (CGM) devices, sexual intercourse is safe for people living with type 1 diabetes.
The study is by Dr Dominica Orłowska, Medical University of Warsaw, Warsaw, Poland, and colleagues.
Sexual intercourse (SI) – as an activity that can consume high levels of energy across various time periods – may be perceived as a risk factor for hypoglycaemia (dangerously low blood sugar) by individuals with diabetes, and hypoglycaemia-related fear can adversely affect intimacy and quality of life.
The authors explain that when they started asking their patients directly about fear of hypoglycaemia during sex, they explained that it does happen. There is also some published evidence: in a survey of 53 young adults with type 1 diabetes, approximately one third reported fear of hypoglycaemia during sexual intercourse
(Pinhas-Hamiel et al., Diabetes Metab Res Rev 2017;33:e2837).
https://onlinelibrary.wiley.com/doi/full/10.1002/dmrr.2837
But importantly, all of the existing evidence comes from questionnaires and interviews. Blood sugar has never before been measured objectively in this context.
Dr Orlowska explains: “On the one hand, sex is physical exertion like any other, and can lower glucose in the same way. But in practice it is different, and our patients tell us so. Exercise can be planned for – you can reduce your insulin dose, eat beforehand, set an activity mode on your pump. Yet sexual activity is usually spontaneous, and it typically happens in the evening or at night, which is already the window of greatest risk for severe and unrecognised hypoglycaemia. And above all, nobody talks about it: patients will discuss exercise with their diabetologist and receive concrete advice, but almost no one asks about sex, so the fear is never addressed. Yet sex life is central to quality of life, and fear of hypoglycaemia can lead people to avoid intimacy.“
In this research, the authors aimed to assess whether sex is associated with an increased risk of hypoglycaemia in adults with T1D based on CGM data.
The study assessed 12 adults with T1D (7 women, 5 men; median age 36 years, range 21-64; mean BMI 24 kg/m²) using CGM (FreeStyle Libre 2 or Guardian 4) who were enrolled in a prospective observational study. Participants were treated with multiple daily injections of insulin (n=6) or insulin pump therapy (n=6; including 2 using automated insulin delivery systems). None of the five male participants reported erectile dysfunction.
Over a 3-month period, participants marked SI events in their CGM application. CGM data collected from 2 hours before to 6 hours after each SI event were analysed. Subgroup analyses assessed the effects of SI timing (daytime 06:00-20:00 vs. Nighttime 20:00-06:00), BMI (under 25 versus 25 and over), diabetes duration, and insulin delivery mode.
A total of 110 SI events were recorded. All participants using insulin pump therapy reported removing their devices during SI. No clinically significant hypoglycaemia was observed. Blood sugar changes were unrelated to insulin therapy mode or diabetes duration.
In 64 events (58%), mean post-SI glucose decreased by 27% (180 to 132mg/dL; statistically significant); in the remaining 46 events (42%), glucose increased by 34% (122 to 164 mg/dL; statistically significant). Both patterns – increasing and decreasing blood glucose – were observed in SI events in every participant.
Higher pre-SI glucose was associated with greater post-SI reduction when decreasing and with a smaller rise when increasing . Nighttime SI (66 events) was associated with a statistically significant reduction in glucose levels (165 to 147 mg/dL), whereas daytime SI (n=44) had no effect (144 to 143 mg/dL). There were no differences between mean glucose recorded for 2 and 6 hours after SI.
Participants in the higher BMI group (25 and over) showed a greater post-SI glucose decrease (−10.7%; 150 to 134 mg/dL, statistically significant) than those with BMI under 25 (−5.6%; 159 to 150 mg/dL; not statistically significant).
The authors conclude:
“Sexual intercourse in adults with T1D does not appear to increase the risk of clinically significant hypoglycaemia, even at night.
Blood sugar responses are bidirectional and seem to be influenced by pre-SI glucose level, BMI, and time of day.
These findings may support clinical counselling and help reduce hypoglycaemia fear-related avoidance of sexual activity in people living with T1D.”
They add a cautionary note about people with T1D not using CGM, explaining:
“In an ideal world, every person with type 1 diabetes should be using CGM.
Those who do not may have no idea whether they are experiencing hypoglycaemia during sex – or, in fact, any setting.”
Dr Dominica Orłowska, Medical University of Warsaw, Warsaw, Poland.
The authors declare no conflicts of interest.
The press release is based on Short Oral Presentation 890 at the Annual Meeting of the European Association for the Study of Diabetes (EASD, Milan, 28 Sept – 2 Oct). No full article is available at this stage. The study has been submitted to a medical journal for publication.
For full abstract click here
or see below
Running marathons with type 1 diabetes can be safe, shows small study using continuous glucose monitoring devices
· Amateur runners with T1D finished the race in a similar time to controls without T1D
· Continuous glucose monitoring (CGM) readings differed significantly from capillary glucose measurements during the marathon; the researchers therefore advise confirming blood glucose levels directly with a glucometer during prolonged endurance exercise, particularly when symptoms and sensor readings do not match
New research to be presented at the Annual Meeting of the European Association for the Study of Diabetes (EASD) in Milan, Italy (Sept 28th – Oct 2nd) shows, with the use of continuous glucose monitoring (CGM) devices people with type 1 diabetes can complete a marathon safely and achieve finishing times similar to runners without diabetes. The study is conducted by Michał Kulecki, Dr Andrzej Gawrecki, and colleagues at Poznan University of Medical Sciences and Raszeja City Hospital, Poznan, Poland.
Completing a marathon with type 1 diabetes (T1D) requires balancing energy expenditure, carbohydrate intake, insulin adjustment, and glucose monitoring. Evidence on blood sugar patterns and CGM accuracy during prolonged endurance exercise under real-life race conditions is limited. The researchers therefore assessed glucose levels, carbohydrate intake, and CGM accuracy during the 2025 Poznań Marathon, a standard 42 km race.
The observational study included 20 amateur runners: 10 with T1D of at least 1 year’s duration and 10 controls without diabetes. For participants with T1D, the target pre-race glucose range was 140-200 mg/dL. Basal insulin dose was reduced by 25% in multiple daily injections and by 50% in non-hybrid insulin pumps, while participants using hybrid closed-loop systems set a target glucose of 150 mg/dL. Five participants used multiple daily injections (MDI), three used continuous subcutaneous insulin infusion (CSII), and two used automated insulin delivery (AID) systems. At five checkpoints (start, 10 km, 19 km, 30 km, and finish), glucose was measured with a glucometer and compared with two CGM systems, one intermittently scanned and one in real-time. The researchers administered carbohydrates or insulin as required. They evaluated CGM accuracy using a standard method for these devices called mean absolute relative difference (MARD), which represents the average absolute percentage difference between sensor glucose readings and reference glucose values.
Participants with and without T1D showed comparable baseline characteristics. They did not differ significantly in age (35.4 vs 39.7 years), and each group included 8 men and 2 women. In the T1D group, participants had a median diabetes duration of 16.5 years and a glycated haemoglobin (HbA1c) of 6.4%. Marathon performance did not differ significantly between groups, with completion times of 228 minutes in T1D and 248 minutes in controls.
During the race, participants with T1D consumed a median of 53.5 g of carbohydrate per hour, equivalent to 2.61 g/kg body weight over the marathon. Capillary glucose measured with the glucometer was 183.5 mg/dL at the start, 119.5 mg/dL at 10 km, 142.5 mg/dL at 19 km, 121.5 mg/dL at 30 km, and 108.5 mg/dL at the finish (median values).
Two hypoglycaemic measurements occurred in the same participant, who nevertheless completed the race. This participant consumed 49.5 g of carbohydrate per hour.
CGM accuracy was reduced during the marathon. CGM readings differed from glucometer measurements by an average of approximately 43% for the intermittently scanned system and 37% for the real-time system and overestimated capillary glucose by +32.2 and +50.4 mg/dL, respectively.
The authors say: “In this small observational study, all runners with type 1 diabetes completed the marathon, with performance comparable to controls. The runner who experienced low blood sugar had started the race with a glucose level below 140 mg/dL. During the marathon, CGM readings differed from glucometer measurements. For longer endurance events, runners should therefore consider checking their glucose with a glucometer, especially when the sensor reading does not match how they feel.”
They add: “Fear of hypoglycaemia is the main barrier to physical activity and affects up to 45% of people with T1D despite the major health benefits of regular exercise. Managing glucose is challenging when glucose levels change rapidly and responses vary between individuals. Our study provides another example that, with appropriate education and careful blood sugar management, people with T1D can successfully take part in even very demanding endurance exercise. ”
But they also explain: ”People with T1D preparing for a marathon should discuss an individual glucose, carbohydrate, and hydration plan with their doctors before the event. The most important aspect is an appropriate insulin management strategy, including reductions in basal and/or prandial insulin. Of course, much depends on baseline blood sugar control, exercise experience, diabetes duration, the presence of diabetes-related complications, and many other individual factors. For example, some people should consult a cardiologist before starting endurance training. Our team supports many athletes with type 1 diabetes who have achieved remarkable goals, including competing at the Olympic Games, completing an Ironman triathlon or running 10 marathons in 10 consecutive days.
Michał Kulecki, Poznan University of Medical Sciences, Poznan, Poland.
Conflict of interest statement for author
M.K.: none A.G-P.: none A.G-W.:M.M.: Bioton, Diagnosis, Proglikemia, Roche Diabetes Care, Ypsomed (honoraria). A.A.: Diagnosis, Medtronic, Synoptis Pharma, Proglikemia, Roche Diabetes Care. A.S.: Proglikemia (support for attending meetings or travel), Roche Diabetes Care, Medtronic. A.K.: Abbott, Diagnosis, Medtronic, Synoptis Pharma, Proglikemia, Roche Diabetes Care (honoraria), Proglikemia (support for attending meetings or travel). M.P.: Abott, Ascensia, Proglikemia, Roche Diabetes Care, Medtronic, Ypsomed (honoraria), Proglikemia (support for attending meetings or travel). A.Ar.: Abbott, Ascensia, Proglikemia, Roche Diabetes Care (honoraria) D.Z-Z.: Abbott, Ascensia, Proglikemia, Roche Diabetes Care, Medtronic (honoraria). A.G.: Abbott, Ascensia, Diagnosis, Medtronic, Proglikemia, Roche Diabetes Care, Synoptis Pharma, Ypsomed (honoraria), Medtronic (support for attending meetings or travel).
The press release is based on Short Oral Presentation 926 at the Annual Meeting of the European Association for the Study of Diabetes (EASD, Milan, 28 September-2 October).
An earlier version of the work, titled “Glycemia assessment in marathon runners with type 1 diabetes,” was presented orally at the XXVII Scientific Congress of the Polish Diabetes Association in Wrocław on 22 May 2026.
No full article on the present study has been published. The authors are happy to answer questions. As this is an oral presentation, there is no poster.
For full abstract click here
or see below
________________
Abstract
Regular exercise has greater impact on reducing risk of type 2 diabetes in younger adults, but the highest absolute benefit in older adults, finds UK Biobank study
Encouraging more older adults to be active could prevent more cases of type 2 diabetes because of their high overall risk
Note this is an early release from the Annual Meeting of the European Association for the Study of Diabetes [EASD].
New research being presented at the Annual Meeting of The European Association for the Study of Diabetes (EASD) in Milan, Italy (Sept 28 – Oct 2), suggests that higher levels of moderate-to-vigorous physical activity (MVPA) are associated with a substantially lower risk of developing type 2 diabetes (T2D), particularly among younger adults.
Over a median follow-up of nearly eight years, the study found that adults younger than 63 years in the lower level exercise group, who did a median of 121 minutes of MVPA per week, had more than double the risk of developing T2D compared with those in the higher-MVPA group, who did a median of 409 minutes per week. In contrast, among adults aged 63 years and older, lower levels of MVPA were associated with a 65% higher relative risk of developing T2D.
However, because older adults have a higher overall risk of T2D, encouraging more adults to be physically active could prevent more cases of T2D among older people.
“The takeaway message is that all adults should be encouraged to be as active as they can, as more physical activity is linked to a lower risk of type 2 diabetes,” said Dr Diana van Heemst from Leiden University Medical Centre, who led the research. “However, at the population level, we may see the greatest reduction in the number of new cases of type 2 diabetes among older adults. Our findings do not support different MVPA timing recommendations for specific population groups.”
Current public health guidelines recommend that adults do at least 150 minutes a week of MVPA that is intense enough to leave you slightly out of breath such as brisk walking, running or cycling.
However, the potential benefits of MVPA for preventing and managing T2D may vary by age and sex, reflecting differences in metabolism and physiological responses to exercise. In addition, underlying metabolic conditions, such as obesity and dyslipidaemia (unusually high levels of cholesterol and other fats in the blood), may influence the relationship between physical activity and the risk of developing T2D.
To find out more, researchers from Leiden University Medical Centre in the Netherlands, set out to look at how both exercise levels (lower vs higher) and timing (late-day vs early-day) affected the risk of developing T2D.
They also examined whether age, sex, and underlying metabolic diseases—including prediabetes, dyslipidaemia, and high blood pressure—modified these associations between exercise and T2D.
The study included data from 87,975 adults without a history of diabetes who were taking part in the UK Biobank study between February 2013 and December 2015. The average age was 63 years, 57% were female, and 97% were white.
The study participants wore an accelerometer device on their wrist for seven consecutive days to record their typical exercise levels. Exercise levels were categorised as lower or higher based on the average number of minutes of weekly MVPA in each age group. This approach helped avoid disproportionately classifying older participants as having lower levels of physical activity.
During an average follow up of 7.7 years, 2,140 participants (2.4%) developed T2D—including 748/44,020 participants in the higher volume exercise group (who had an overall median of 409 minutes MVPA/week) and 1,392/43,955 participants in the lower volume exercise group (who had an overall median of 121 minutes).
The analysis found that participants in the lower MVPA group, who did not meet the recommended 150 minutes per week, had twice the relative risk of developing T2D compared with those in the higher MVPA group, after adjusting for potential confounders, including age, sex, ethnicity, education, deprivation, smoking status, sleep duration and family history of diabetes.
Additionally, adults who did most of their exercise later in the day, from 1pm to midnight, had a 10% lower relative risk of T2D than those who exercised earlier, from 5am to before 1pm.
_____________________________________________
ABSTRACT
Benefits of physical activity greatest in older adults
Importantly, the analysis found that both age and underlying pre-diabetes influenced the relationship between physical activity and T2D risk.
Among younger adults (aged younger than the average population age of 63 years), lower levels of MVPA were associated with more than twice the relative risk of developing T2D compared with higher levels of MVPA. In contrast, among older adults (older than 63 years), lower levels of MVPA were associated with a 65% higher relative risk of T2D.
The time of day also appeared to matter more for younger adults. Exercising later in the day was associated with a 23% lower risk of T2D among younger adults, compared with a 4% lower risk among older adults.
The association was also stronger among people without prediabetes, with lower levels of MVPA associated with more than twice the relative risk of developing T2D compared with higher levels. In contrast, among those with prediabetes, lower levels of MVPA were associated with a 54% higher relative risk of developing T2D.
When the analysis comparing lower and higher levels of MVPA was broken down into five-year age groups, the relative risk of developing T2D declined with increasing age. However, the T2D incidence rates difference increased substantially with age in the overall population, meaning that the absolute benefit of physical activity was greater in older age groups.
For example, the decrease in relative risk estimates comparing lower with higher MVPA levels with increasing age was more pronounced in women than in men. Among women, the difference in T2D incidence rates remained relatively stable across age groups. Among men, the absolute difference in incidence rates was larger and increased steeply with age.
According to author Qiuyu Feng from Leiden University Medical Centre, “Our findings underscore why it is important to look at both relative and absolute risk when considering the public health impact of physical activity. Relative risk alone does not capture how much physical activity could help reduce the number of cases in different population groups.”
The researchers note several limitations to the study, including that the study population was not representative of the UK population, as UK Biobank participants are known to be generally healthier, wealthier and better educated than the wider population. In addition, pre-diabetes status was assessed several years before physical activity was measured using accelerometers and may have changed over time, which could have underestimated the findings.
Qiuyu Feng was supported by a scholarship from the China Scholarship Council. The research was supported by a grant from the Dutch Research Council.
The press release is based on short oral presentation 0300 at the Annual Meeting of the European Association for the Study of Diabetes (EASD, Milan, September 28 – October 2).
As the full paper is provided, there is no link to the abstract.
The full paper was recently published in Diabetes, Obesity and Metabolism: Age‐Specific Associations of Moderate‐to‐Vigorous Physical Activity With Relative and Absolute Risk of Type 2 Diabetes in UK Biobank Participants – Feng – Diabetes, Obesity and Metabolism – Wiley Online Library
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