Lemmens et al. The Journal of Headache and Pain (2019) 20:16 The Journal of Headache https://doi.org/10.1186/s10194-019-0961-8 and Pain REVIEWARTICLE Open Access The effect of aerobic exercise on the number of migraine days, duration and pain intensity in migraine: a systematic literature review and meta-analysis Joris Lemmens1, Joke De Pauw1, Timia Van Soom1, Sarah Michiels1,2,3, Jan Versijpt4, Eric van Breda1, René Castien5,6 and Willem De Hertogh1* Abstract Background: In patients with frequent migraine, prophylactic treatments are used. Patients often request non- pharmacological alternatives. One treatment option can be aerobic exercise. The value of aerobic exercise as prophylactic treatment however needs to be determined. Methods: A systematic review and meta-analysis was performed to investigate the result of aerobic exercise on the number of migraine days, duration and pain intensity in patients with migraine. After screening three online databases, PubMed, Cochrane library and Web of Science, using predefined in- and exclusion criteria, six studies were retained. Pooling of data was performed when possible. Results: Significant reductions in the number of migraine days after aerobic exercise treatment were found with a mean reduction of 0.6 ± 0.3 migraine days/month. Other outcomes were too variable to pool due to heterogeneity of outcome measurements. Unpooled data revealed small to moderate reductions in attack duration (20–27%) and pain intensity (20–54%) after aerobic exercise intervention. Various exercise intensities are applied. Conclusion: There is moderate quality evidence that in patients with migraine aerobic exercise therapy can decrease the number of migraine days. No conclusion for pain intensity or duration of attacks can be drawn. Effect sizes are small due to a lack of uniformity. For future studies, we recommend standardized outcome measures and sufficiently intense training programs. Trial registration: CRD42018091178. Keywords: Migraine, Headache, Physical therapy, Exercise, Treatment, Headache characteristics Introduction The use of a prophylactic treatment is recommended Worldwide, migraine is the second most disabling dis- if headache is present more than 8 days per month, dis- order [1]. Additionally, in the age group 15–49 years, mi- ability is present despite acute medication, headache is graine is the top cause of years lived with disability [1], present more than three days per month when acute magnifying its impact on the working population [1]. On medication is not effective [3–6]. These prophylactic average eighteen days per year per migraine patient are drugs, however, might not be tolerated that well by pa- missed from work or household activities. Mean annual tients or patients might request non-pharmacological al- costs per-person are €1222 for migraine, which leads to ternatives [4, 7, 8]. In migraine, other non-drug related high costs for society [2]. prophylactic treatments like self-management strategies, manual therapy and aerobic exercise are also being * Correspondence: [email protected] employed [9–14]. In aerobic exercise, a moderate inten- 1 Department of Rehabilitation Sciences and Physiotherapy, Faculty of sity training is performed over a longer period of time, Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium Full list of author information is available at the end of the article e.g. 30 min. © The Author(s). 2019 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Lemmens et al. The Journal of Headache and Pain (2019) 20:16 Page 2 of 9 The rationale for using aerobic exercise in migraine is screening). Two authors (W.D.H. and J.L.) independently based on the fact that exercise can play a substantial role screened the selected full texts (second screening). In in the modulation of pain processing [15–18]. Moreover, case the two authors had diverging opinions, a third au- the analgesic effects of both short-term [16] and thor (J.D.P.) was consulted and a decision was made by long-term [15, 18] aerobic exercise have been observed consensus. Articles were included in the meta-analysis, at both a central and peripheral level [15, 16, 18]. when data-pooling was feasible based on identical diag- In 2008, the first narrative review on the effect of aer- nosis (ICHD) and units of outcome measurement. obic exercise in the treatment of migraine showed promis- ing, though inconclusive results [19]. During the past Data items and collection decade, new studies on the use of exercise as a prophylac- Data were manually extracted from the reports by two tic treatment in migraine have been published. The up- researchers (S.M. and J.L.). The reports were searched dated version of the International Classification of for the following variables: sample size characteristics Headache Disorders (ICHD-III) [20] specifically indicates (migraine diagnosis); experimental intervention charac- there is a need for a thorough and systematic overview re- teristics; exercise intensity; control group characteristics garding the effects of aerobic exercise in migraine. and intervention; follow-up period; results of outcome Therefore, the aim of the present study is to measures (the number of migraine days, duration of at- summarize the literature published after 2004 on the ef- tacks and pain intensity) and confounding factors. fectiveness of aerobic exercise in migraine. The research To pool data, the random effect model and RevMan question of this systematic review is: what is the effect of software (version 5.3) was used to compute a mean differ- aerobic exercise on the number of migraine days, dur- ence between the data of the intervention and control ation and pain intensity in patients with migraine? group. For missing standard deviations the p-value or con- fidence intervals were used to calculate the missing value. Methods These calculations are based on the calculations provided Search strategy in the Cochrane Handbook [23]. Before entering the mean The format of this systematic review was based on the Pre- values in the model, the difference was computed between ferred Reporting Items for Systematic reviews and pre-and post-intervention data of the intervention and Meta-analyses (PRISMA) [21](Additionalfile1). To estab- control group as it demonstrates the mean reduction in lish a search strategy, the PICO format was used [22]. migraine days. A PROSPERO record of this systematic re- Three electronic databases were searched to identify eligible view has been registered (ID: CRD42018091178). studies: PubMed, the Cochrane library for trials and Web of Science (from January 1, 2004 till February 21, 2018). An Risk of bias in the individual studies additional search for grey literature was not performed. In- Risk of bias assessment of the selected articles was per- clusion and exclusion criteria were determined as depicted formed using the Cochrane risk of bias tool (ROB) for in Table 1. The specific search strategy used for PubMed, randomized controlled trials (RCTs). This checklist can the Cochrane library for trials and Web of Science is shown be found in Figs. 1 and 2. Two reviewers (T.V.S. and in detail in Table 1 and Additional file 2. J.L.) evaluated the included articles independently. The items of the ROB assessment were rated as “1”, “0”,or Study selection “?”. An item was rated “1” if sufficient information was Based on the predefined inclusion and exclusion criteria available and bias was unlikely. An item was rated “0” if the included studies were screened on title and abstract sufficient information was available but the article did by two investigators (S.M. and J.L.) independently (first not meet a specific criterion. An item was rated “?” if Table 1 PICOS and eligibility criteria Inclusion criteria Exclusion criteria Patients (P) Migraine with or without aura classified by ICHD-II Non-human subjects (such as models or animals), other types of headache or pregnant women Intervention (I) Physical endurance, physical fitness, aerobic exercise, Manual therapy or medication as stand-alone treatment or no intervention exercise therapy performed during at least 6 weeks such as diagnosing or performing tests on patients Control (C) –– Outcome (O) Number of migraine days, attack frequency, pain intensity or duration of migraine attacks Study design (S) Randomized clinical trials, randomized controlled Non-English, non-Dutch or non-French; studies published before trials or clinical trial January 1, 2004; cohort studies, case control studies, case reports, reviews or meta-analyses Lemmens et al. The Journal of Headache and Pain (2019) 20:16 Page 3 of 9 To measure the level of evidence of each study the classification of the Dutch CBO (Centraal BegeleidingsOrgaan-classificatiesysteem) [30]wasused (Table 2). Results Study selection The search strategy yielded 83 results in PubMed, 53 in the Cochrane library for trials and 194 in Web of Science. After removal of duplicates, 265 articles were screened on title and abstract. Fifteen studies were retrieved and screened on full text by two researchers (W.D.H. and J.L.). After screening on full text, six studies were found eligible and were included in this review (Fig. 3). Study characteristics The included studies were all RCTs, except for one con- trolled clinical trial (CCT) [25]. All studies included patients with migraine classified by the ICHD-II as mentioned in the inclusion criteria. In three studies, patients were excluded if they performed any kind of regular aerobic training before the start of the study [25]oratleast12weekspriortothe study [26, 28]. The number of patients enrolled in the differ- ent studies ranged from 16 to 110 with a total number of 357 patients with migraine. The mean age of all included patients was 38 years and 88% of them were women.