{"doi":"10.1093/sleep/zsad214","title":"Clinical nightmare frequency and its association with reduced physical health during military operations","abstract":"Recurrent nightmares affect up to 8% of the general population and over 50% of those with a post-traumatic stress disorder (PTSD) diagnosis [1]. Despite known associations between nightmares and negative mental health outcomes [2], little is known concerning how nightmares relate to physical health outcomes. Disruptions to sleep micro- and macro-architecture in frequent nightmare recallers [3] would suggest that they also exhibit reduced physical health, yet prior findings on this topic are mixed. Self-reported survey studies observed negligible relationships between nightmare frequency and physical activity [4]. More research is needed to better understand the contribution of nightmares to physical health, especially in at-risk populations. One such population—military personnel—exhibits a high nightmare prevalence that is associated with PTSD outcomes [5]. Military personnel strives to maintain optimal human performance levels under demanding occupational and environmental conditions, and a recent survey of US reserve personnel found frequent physical health complaints from those who experienced nightmares and insomnia [6]. To better understand the relevant issues, the current study draws from multiple diverse data sources to investigate the link between nightmares and health outcomes through a prospective longitudinal analysis of US Navy personnel before and during at-sea operational training. A longitudinal dataset of US Navy sailors (N = 696) completed extensive health surveys before, during, and after at-sea training. Mean age of sailors was 28 years (SD = 7) and 82% identified as male (18% as female). Sailor paygrades were 17% Officer and 82% Enlisted (35% E1-4, 35% E5-6, and 12% E7-9). Before the training period, sailors self-reported baseline nightmare recall frequency (NMRF) on an 8-point Likert scale (How often have you experienced nightmares in the past several months?). Responses were binned into clinical (≥1 per week) and non-clinical nightmare frequency. During the underway, sailors (n = 598) wore an Oura ring for multiple days/nights (M ± SD = 17 ± 11) and completed daily health surveys (M = 8 ± 5). The Oura is a personal status monitor and was used to track common sleep summary (duration, onset latency, and efficiency) and daily activity (energy expenditure or metabolic equivalent of task; MET) measures. The output of Oura’s proprietary algorithms have been validated as an effective alternative to polysomnography and actigraphy for sleep summary outcomes [7] and an alternative to accelerometers for energy expenditure outside the laboratory [8]. The daily health surveys were completed in the morning and asked questions about the prior day’s energy levels (Were you exhausted and unable to function effectively?) and ability to communicate (Were you able to communicate effectively with others?) on 5-point Likert scales. After the at-sea period, sailors retrospectively self-reported characteristics of the training period, including NMRF, sleep quality (Pittsburgh Sleep Quality Index; PSQI), the number of days they experienced poor physical health (Thinking about your physical health, which includes physical illness and injury, how many days during the past 30 days was your physical health not good?), and the number of days they experienced poor mental health (Thinking about your mental health, which includes stress, depression, and problems with emotions, how many days during the past 30 days was your mental health not good?). The change in percentage of sailors with clinical NMRF from before to during the at-sea period was compared using a bootstrap resampling test. Each of 10 000 iterations involved resampling with replacement of each population, calculating frequencies, and subtracting the difference (during minus before). Statistical significance (ie, P-value) was determined by taking the proportion of difference values greater than zero and multiplying this by two for a two-tailed test. Both NMRFs were tested ","journal":"SLEEP","year":2023,"id":378936,"datarank":0.16479184330021646,"base_score":1.0986122886681096,"endowment":1.0986122886681096,"self_citation_contribution":0.16479184330021646,"citation_network_contribution":0.0,"self_endowment_contribution":0.16479184330021646,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":2,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9588,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2023-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1143090,"name":"Jason Jameson","orcid":"0000-0002-0487-3445","position":1,"is_corresponding":false},{"id":239726,"name":"Ken A. Paller","orcid":"0000-0003-4415-4143","position":2,"is_corresponding":false},{"id":336420,"name":"Rachel R. Markwald","orcid":"0000-0002-0432-3937","position":3,"is_corresponding":false},{"id":1143091,"name":"Dale W. Russell","orcid":"0000-0003-4289-1270","position":4,"is_corresponding":false},{"id":626199,"name":"Remington Mallett","orcid":"0000-0001-6183-3098","position":0,"is_corresponding":true}],"reference_count":16,"raw_metadata":{"citation_network_status":"fetched"},"created_at":"2026-07-19T01:16:48.594070Z","pmid":"37632739","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}