May Grydeland

• Solberg, Aleksander; Grydeland, May; Nilsen, Tormod Skogstad; Storås, Anne Marie Holck; Davis, Ian D. & Greaves, Natalie [Show all 23 contributors for this article] (2026). Prevalence of meeting aerobic physical activity and resistance training guidelines in advanced prostate cancer: a descriptive study of racial and regional disparities in the IRONMAN registry. Supportive Care in Cancer. ISSN 0941-4355. 34. doi: 10.1007/s00520-026-11251-3. Full text in Research Archive Show summary

  Purpose To estimate guideline-based aerobic physical activity and resistance training participation in an international population of people with newly diagnosed metastatic hormone-sensitive or castration-resistant prostate cancer, and to assess racial and regional differences. Methods Participants in the international IRONMAN registry (NCT 03151629) of advanced prostate cancer reported leisure-time activity at 6, 18, and 30 months post-enrolment. The proportion meeting guidelines of≥150 min/week moderate to vigorous physical activity and≥2 weekly resistance training sessions were quantified. Mixed-effects logistic regression estimated odds of meeting guidelines averaged across timepoints using all follow-up data by self-identified race (White, Black, Other) and geographic region (Europe, Australia, North America, Africa, Other). Results Among 2485 participants, 58–63% met aerobic physical activity guidelines and 19–23% met resistance training guidelines across timepoints. Resistance training participation was especially low in African geographic regions (0–3%). Participants self-identifying as Black had lower odds of meeting aerobic physical activity guidelines than White participants (crude odds ratio [cOR] 0.23, 95% CI 0.15–0.36), and participants from Africa had lower odds than those from Europe (cOR 0.08, 95% CI 0.03–0.21). Crude patterns were similar for resistance training. Aerobic physical activity disparities persisted after multivariable adjustments, and in sensitivity analyses excluding Black participants from African geographic regions, while resistance training estimates were attenuated. Conclusions Targeted strategies are warranted to increase participation rates in aerobic physical activity and resistance training among advanced prostate cancer patients self-identifying as Black, or those from African geographic regions.

• Bratteteig, Mari; Grydeland, May; Anderssen, Sigmund Alfred; Ruud, Ellen; Torsvik, Ingrid Kristin & Thorsen, Lene [Show all 14 contributors for this article] (2026). Weekly physical activity trajectories in short- and long-term survivors of childhood cancer: the PACCS and SURfit studies. Journal of cancer survivorship. ISSN 1932-2259. doi: 10.1007/s11764-026-02086-2. Full text in Research Archive Show summary

  Purpose Identify and describe weekly physical activity (PA) trajectories in adolescent and adult childhood cancer survivors (survivors), describe characteristics of survivors following different PA trajectories, and compare PA trajectories to controls. Methods This study includes adolescent (9–18 years) survivors and controls from the Physical Activity in Childhood Cancer Survivors (PACCS) study and adult (18–49 years) survivors from the survivor fitness (SURfit) study and controls from the Norwegian National Physical Activity Survey 2. Weekly trajectories of accelerometer-measured PA were identified by multivariate latent class mixed models using daily minutes of moderate-to-vigorous and light PA (MVPA, LPA). Survivors’ characteristics related to different PA trajectories were assessed using a descriptive approach, and PA trajectories between survivors and controls were visually compared. Results We identified four PA trajectories among adolescents (Low regular; Medium, drop weekend; Medium, peak Friday; and Medium regular) and four among adult survivors (Medium regular; Medium, drop weekend; Medium regular MVPA, high regular LPA; and High, drop weekend). The main factors related to the different PA trajectories were sex, age at assessment, sleep, and (parental) education, whereas diagnosis seemed important in adolescent survivors only. In adolescents, trajectories were comparable between survivors and controls, while in adults, only three trajectories were comparable. The allocation to the different trajectories was more favorable in adolescent survivors (fewer in the Low trajectory) and adult survivors (no Low regular MVPA trajectory was identified in survivors) compared to controls. Implications for Cancer Survivors Our findings show many different behavioral approaches to accumulate PA over a week. They highlight the need for targeted PA interventions in a subset of survivors (i.e., adolescent, female survivors of CNS tumors). Developing interventions to prevent PA drops on the weekend holds high potential.

• Johansen, Sara Hassing; Edvardsen, Elisabeth; Raastad, Truls; Ruud, Ellen; Deng, Wei Hai & Bratteteig, Mari [Show all 10 contributors for this article] (2026). Associations Between Physical Fitness and Fatigue in Adolescent Childhood Cancer Survivors: The PACCS Study. Pediatric Blood & Cancer. ISSN 1545-5009. doi: 10.1002/1545-5017.70478. Full text in Research Archive
• Johansen, Sara Hassing; Reinertsen, Kristin Valborg; Wisløff, Torbjørn; Sæter, Mali; Sarvari, Sebastian & Kiserud, Cecilie E. [Show all 11 contributors for this article] (2025). Effects of aerobic exercise on late effects and quality of life in long-term breast cancer survivors: A randomized controlled trial. JNCI Cancer Spectrum. 9(6). doi: 10.1093/jncics/pkaf102. Full text in Research Archive Show summary

  Background Breast cancer survivors (BCSs) are at increased risk of late effects. While research has reported positive effects of exercise therapy on fatigue and health-related quality of life (HRQoL) among short-term BCSs, evidence in long-term survivors remains scarce. Methods The CAUSE (CArdiovascUlar Survivors Exercise) trial was a 2-armed randomized controlled trial. Long-term BCSs were assigned to 5 months of thrice-weekly supervised aerobic exercise or usual care. Late effects and HRQoL were assessed by Chalder Fatigue Questionnaire, European Organization for Research and Treatment of Cancer QLQ-BR23 and QLQ-C30 questionnaires, and Scale for Chemotherapy-Induced Long-term Neurotoxicity at baseline (T0), post-intervention (T1), and 1-year follow-up (T2). Results In total, 140 BCSs (mean age 59.0 ± 6.4 years, 11 ± 1 years post-treatment) were included. Loss to follow-up at T1 was 6% and 19% in the exercise- and usual care group, respectively. From T0 to T1, the exercise group significantly improved total fatigue (between groups mean difference [MD] = –3.0, P < .001), body image (MD = 6.7, P = .043), physical- (MD = 3.2, P ≤ .001), role- (MD = 9.6, P = .019), and cognitive function (MD = 3.4, P = .038), insomnia (MD = –9.0, P = .017), and global health/QoL (MD = 5.3, P ≤ .001) compared to usual care. The exercise benefits were more pronounced in BCSs experiencing versus not experiencing late effects at baseline. At 1-year follow-up, most improvements regressed toward baseline values. Conclusion Aerobic exercise significantly improves fatigue, body image, physical-, role-, and cognitive function, insomnia, and HRQoL in long-term BCSs. These findings suggest that exercise therapy should be a core component of managing late effects and enhancing HRQoL in long-term BCSs. Clinical trial registration URL: https://www.clinicaltrials.gov/. Registration number: NCT04307407

• Johansen, Sara Hassing; Sæter, Mali; Sarvari, Sebastian; Reinertsen, Kristin Valborg; Edvardsen, Elisabeth & Wisløff, Torbjørn [Show all 18 contributors for this article] (2025). Effects of Aerobic Exercise on Cardiorespiratory Fitness and Cardiovascular Risk Factors in Long-Term Breast Cancer Survivors: A Randomized Controlled Trial. JACC: CardioOncology. 7(4), p. 414–426. doi: 10.1016/j.jaccao.2025.04.006. Full text in Research Archive
• Edvardsen, Elisabeth; Ruud, Ellen; Rueegg, Corina Silvia; Kvidaland, Haakon Kristian; Torsvik, Ingrid Kristin & Bovim, Lars Peder Vatshelle [Show all 11 contributors for this article] (2025). Physical Fitness and Physical Activity in Adolescent Childhood Cancer Survivors and Controls: The PACCS Study. Medicine & Science in Sports & Exercise. ISSN 0195-9131. 57(10), p. 2286–2293. doi: 10.1249/MSS.0000000000003758. Full text in Research Archive Show summary

  Objectives This study aimed to compare physical fitness, function, and physical activity (PA) in adolescent childhood cancer survivors (CCSs) to age- and sex-matched controls and across different cancer diagnoses. Methods This multicenter cross-sectional study (Physical Activity among Childhood Cancer Survivors) included CCSs aged 9–18 yr (≥1-yr after cancer treatment) and age- and sex-matched controls. Physical fitness tests included cardiorespiratory fitness (V̇O2max) and muscular strength (maximal isometric handgrip, knee extension, and chest press). Physical function tests included a 1-min sit-to-stand test (STS) and countermovement jump (CMJ). PA was measured by accelerometer for 7 d. We used linear mixed-effects models to compare outcomes between CCSs and controls, and across diagnostic groups. Results We included 157 CCSs and 113 controls aged 13.4 ± 2.6 yr (mean ± SD). Cancer types were leukemia (n = 78), central nervous system (CNS) tumors (n = 18), lymphoma (n = 16), and other solid tumors (n = 45). CCSs had lower V̇O2max (marginal mean (95% confidence interval), 41.7 (38.4–45.0) vs 46.4 (42.9–49.8) mL·kg−1·min−1; P < 0.001), knee-extension strength (35.4 (34.1–36.8) vs 38.2 (36.7–39.7) kg, P = 0.003), chest-press strength (30.0 (28.4–31.6) vs 32.8 (31.0–34.7) kg, P = 0.007), STS repetitions (57.5 (55.8–59.3) vs 60.0 (58.0–62.0) P = 0.017), and CMJ height (22.1, (20.5–23.8) vs 24.9 (23.2–26.6) cm, P < 0.001). PA levels and sedentary time were similar in both groups (8513 (7993–9034) vs 9000 (8404–9596) steps per day, P = 0.174, respectively). Survivors of CNS tumors had the lowest values for V̇O2max, muscular strength, physical function, and PA. Conclusions Despite no significant difference in PA levels, adolescent CCSs had 4.2% to 11% lower physical fitness and function compared with controls, where survivors of CNS tumors performed the poorest.

• Bratteteig, Mari; Rueegg, Corina Silvia; Lie, Hanne Cathrine; Thorsen, Lene; Larsen, Elna Hamilton & Larsen, Marie Hamilton [Show all 14 contributors for this article] (2024). Physical activity behaviors and screen time in young childhood cancer survivors: the Physical Activity in Childhood Cancer Survivors Study. Journal of cancer survivorship. ISSN 1932-2259. doi: 10.1007/s11764-024-01671-7. Full text in Research Archive Show summary

  Purpose: In childhood cancer survivors (CCS), high physical activity (PA) and low sedentary time may reduce risks of late-effects. PA behaviors and screen time, and how they relate to moderate-to-vigorous PA (MVPA) in CCS, are largely unknown. We examined PA behaviors and screen time, and their cross-sectional associations with MVPA. Methods: CCS from any cancer diagnosis (≥ l year post-treatment), aged 9–16 years at study, were eligible in the international Physical Activity in Childhood Cancer Survivors (PACCS) study. PA behaviors (school transport, intensity-effort in physical education (“PE intensity”), leisure-time PA) and screen time were assessed by self-report, and MVPA by accelerometers (ActiGraph GT3X-BT). Multivariable linear regressions were used to assess associations between PA behaviors and screen time with MVPA. Results: We included 481 CCS (48% girls, mean age 12.2 years). Passive school transport (prevalence 42%) was associated with 10% lower MVPA/day (β = 6.6 min, 95% CI 3.3–10.0), low PE

• Bratteteig, Mari; Rüegg, Corina Silvia; Raastad, Truls; Grydeland, May; Torsvik, Ingrid Kristin & Schindera, Christina [Show all 8 contributors for this article] (2023). Physical Activity, Fitness, and Cardiovascular Disease Risk in Adolescent Childhood Cancer Survivors Compared to Controls: The Physical Activity in Childhood Cancer Survivors Study. Journal of Adolescent and Young Adult Oncology. ISSN 2156-5333. p. 1–9. doi: 10.1089/jayao.2023.0063. Full text in Research Archive Show summary

  Purpose: Childhood cancer survivors have increased risk of cardiac late effects that can be potentially mitigated by physical activity and fitness. We aimed to (1) compare cardiovascular disease (CVD) risk between survivors and controls, and (2) examine whether the associations of moderate-to-vigorous physical activity (MVPA), cardiorespiratory fitness (CRF), and musculoskeletal fitness (MSF) with CVD risk factors differed between survivors and controls. Methods: Within the Physical Activity in Childhood Cancer Survivors (PACCS) study, we assessed CVD risk factors (android fat mass, systolic blood pressure [SBP], total cholesterol/high-density lipoprotein [HDL]-cholesterol, and glycosylated hemoglobin) in 157 childhood cancer survivors and 113 age- and sex-matched controls aged 9–18 years. We used multivariable mixed linear regression models to compare CVD risk factors between survivors and controls, and assess associations of MVPA, CRF, and MSF with CVD risk factors. Results: Compared with controls, survivors had more android fat mass (861 vs. 648 g, p = 0.001) and lower SBP (114 vs. 118 mmHg, p = 0.002). MVPA, CRF, and MSF were associated with lower levels of android fat mass and total cholesterol/HDL-cholesterol, and higher SBP in survivors. Associations of MVPA, CRF, and MSF with CVD risk factors were similar in survivors and controls (Pinteraction > 0.05), except the associations of CRF and MSF with android fat mass, which were stronger in survivors than in controls (Pinteraction ≤ 0.001). Conclusion: Owing to higher levels of android fat mass and its stronger association with physical fitness in childhood cancer survivors compared with controls, survivors should get targeted interventions to increase fitness to reduce future risk of CVD.

• Grydeland, May; Bratteteig, Mari; Rüegg, Corina Silvia; Lie, Hanne Cathrine; Thorsen, Lene & Larsen, Elna Hamilton [Show all 14 contributors for this article] (2023). Physical Activity Among Adolescent Cancer Survivors: The PACCS Study. Pediatrics. ISSN 0031-4005. 152(3). doi: 10.1542/peds.2023-061778. Full text in Research Archive Show summary

  OBJECTIVES: Physical activity (PA) may modify risks of late effects after cancer. We aimed to examine levels of PA and sedentary time (ST) in a large, international sample of adolescent childhood cancer survivors in relation to sociodemographic and cancer-related factors and compare levels of PA and ST to reference cohorts. METHODS: Survivors from any cancer diagnosis who had completed cancer treatment ≥1 year ago, aged 9 to 16 years, were eligible for the multicenter Physical Activity in Childhood Cancer Survivors study. PA and ST were measured by ActiGraph GT3X+ accelerometers. We performed linear regression analyses to assess factors associated with moderate-to-vigorous PA (MVPA) and ST, and compared marginal means of total PA, MVPA, and ST in 432 survivors to sex- and age-stratified references (2-year intervals) using immediate t-tests for aggregated data. RESULTS: Among survivors, 34% fulfilled the World Health Organization’s PA recommendation of ≥60 min of daily MVPA on average and their ST was 8.7 hours per day. Being female, older, overweight, a survivor of central nervous system tumor, or having experienced relapse were associated with lower MVPA and/or higher ST. Generally, male survivors spent less time in MVPA compared with references, whereas female survivors had similar levels. Both male and female survivors had higher ST than references in nearly all age groups. CONCLUSIONS: The low PA and high ST in this large sample of adolescent childhood cancer survivors is worrisome. Combined, our results call for targeted interventions addressing both PA and ST in follow-up care after childhood cancer.

• Matlary, Ruth Elise Dybvik; Grydeland, May; Glosli, Heidi; Rüegg, Corina Silvia & Holme, Pål Andre (2023). Factors associated with physical activity in young people with haemophilia A on prophylaxis. Haemophilia. ISSN 1351-8216. 29(3), p. 900–909. doi: 10.1111/hae.14776. Full text in Research Archive Show summary

  Introduction: Physical activity (PA) is influenced by numerous factors, and the literature describing why people with haemophilia (PWH) are physically active or not is inconclusive. Aims: To investigate factors associated with PA (mean min/day in light (LPA), moderate (MPA), vigorous (VPA) and total PA, and proportion meeting World Health Organization (WHO) weekly moderate-to-vigorous (MVPA) recommendations) among young PWH A. Methods: Forty PWH A on prophylaxis from the HemFitbit study were included. PA was measured using Fitbit devices and participant characteristics were collected. Potential factors associated with PA were investigated by univariable linear regression models for continuous PA outcomes, and descriptively for teenagers meeting/not meeting WHO MVPA recommendations only, because all except one adult met PA recommendations. Results: Mean age (n = 40) was 19.5 years (SD 5.7). Annual bleeding rate was nearly zero and joint scores were low. We found an increase of four min/day in LPA (95% confidence interval (CI) 1–7) per year increase in age. Participants with ‘Haemophilia Early Arthropathy Detection with Ultrasound’ (HEAD-US) score ≥1 engaged in mean 14 min/day less MPA (95% CI −23.2 to −3.8), and 8 min less VPA (95% CI −15.0 to −0.4) compared to participants with HEAD-US score 0. Teenagers who met PA recommendations had slightly better joint status compared to those who did not meet recommendations. Conclusion: These findings indicate that presence of mild arthropathy does not affect LPA but may have a negative impact on PA of higher intensities. Early start of prophylaxis may be an important determinant of PA.

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