Effect of bittern immersion on textural properties and water-holding capacity in beef.

Hard meat has low market value; hence, we used bittern as a novel meat tenderizer for bovine M. semitendinosus, one of a hard muscle. We investigated the effects of beef immersion in bittern, a basic solution primarily comprising MgCl2, on textural properties and water-holding capacity. Muscle samples from M. semitendinosus of Holstein steers were immersed in seven different solutions (RO, NaCl, MgCl2, red wine, pH 3, bittern, and pH 8) and heated at 80°C for 5min. The pH of the beef and immersion solutions, water-holding capacity, and maximum load of the meat were measured. Although beef immersed in red wine (pH 3) had a lower pH and water-holding capacity, that immersed in bittern (pH 8.4) had a higher pH and higher water holding capacity. These results indicate that immersion in acidic red wine may harden beef and that immersion in basic bittern may be more effective in maintaining water-holding capacity and softening beef.

Plant Micropropagation and Temporary Immersion Systems.

Temporary immersion systems (TIS) have been widely recognized as a promising technology for micropropagation of various plant species. The TIS provides a suitable environment for culture and allows intermittent contact of the explant with the culture medium at different immersion frequencies and aeration of the culture in each cycle. The frequency or immersion is one of the most critical parameters for the efficiency of these systems. The design, media volume, and container capacity substantially improve cultivation efficiency. Different TIS have been developed and successfully applied to micropropagation in various in vitro systems, such as sprout proliferation, microcuttings, and somatic embryos. TIS increases multiplication and conversion rates to plants and a better response during the ex vitro acclimatization phase. This article covers the use of different immersion systems and their applications in plant biotechnology, particularly in plant tissue culture, as well as its use in the massive propagation of plants of agroeconomic interest.

Hot-Water Immersion (HWI) or Ice-Pack Treatment (IPT) as First Aid for Human Envenomation by Marine Animals? Review of Literature.

Envenomation by marine animals poses a significant health concern globally, affecting both local residents and tourists in coastal regions. The primary objective of this review is to critically evaluate the existing scientific literature to determine the most effective first-aid treatment for envenomations caused by marine animals, specifically whether hot-water immersion (HWI) or ice-pack treatment (IPT) provides the best immediate care. This comprehensive review covers a wide range of marine envenomations, from jellyfish stings to stingray injuries. While our focus is primarily on the efficacy of HWI and IPT, we also explore the role of cold-water treatment as a result of its relevance and similarity to ice-pack applications. In addition, we examine other treatments mentioned in the literature, such as medications or vinegar, and highlight their findings where applicable. To provide a clear and structured overview, we summarised the articles in separate tables. These tables categorise the type of research conducted, the marine species studied, the region of origin of the marine species, and the key findings of each study. Our analysis of the available evidence indicates a general consensus in the scientific community on the effectiveness of HWI or IPT for envenomation by marine animals. However, when treating those injuries, it is crucial to consider all factors since there is no universally superior treatment due to the diverse nature of marine habitats.

EVALUATION OF IMMERSION IN EMULSIFIED ISOFLURANE OR PROPOFOL AS PART OF A TWO-STEP EUTHANASIA PROTOCOL IN MARBLED CRAYFISH (PROCAMBARUS VIRGINALIS).

The marbled crayfish (Procambarus virginalis) is a parthenogenetic invasive species across much of the world, and when found, euthanasia is often recommended to reduce spread to naïve ecosystems. Euthanasia recommendations in crustaceans includes a two-step method: first to produce nonresponsiveness and then to destroy central nervous tissue. Minimal data exist on adequate anesthetic or immobilization methods for crayfish. A population of 90 marbled crayfish was scheduled for euthanasia due to invasive species concerns. The population was divided into six treatment groups to evaluate whether immersion in emulsified isoflurane or propofol solutions could produce nonresponsiveness. Each group was exposed to one of six treatments for 1 h: isoflurane emulsified at 0.1%, 0.5%, 2%, 5%, and 15% or propofol at 10 mg/L and then increased to 100 mg/L. Crayfish from all treatment groups were moved to nonmedicated water after completion of 1 h and observed for an additional 4 h. All crayfish treated with isoflurane showed lack of a righting reflex at 5 min and loss of movement after 30 min. By 240 min (4 h), none of the crayfish from the isoflurane treatment groups regained movement. None of the crayfish in the propofol treatment achieved loss of reflexes or responsiveness, and all remained normal upon return to nonmedicated water. Isoflurane emulsified in water produces nonresponsiveness that is appropriate for the first step of euthanasia, while propofol was insufficient at these treatment doses.

Evaluation of eye and serum findings in different waters in rabbits by drowning and submersion modeling.

Background/aim: This study investigated serum, vitreous, and anterior chamber fluid electrolyte changes, corneal thickness (CT), corneal volume (CV), anterior chamber volume (ACV), and anterior chamber depth (ACD) as an auxiliary diagnostic method in the identification of drowning in fresh or salt water. Materials and methods: The study used 35 healthy, adult, male, white New Zealand rabbits, seperated into five groups (control, saltwater drowning (SWD), saltwater immersion (SWI), freshwater drowning (FWD), freshwater immersion (FWI)). CT, CV, ACV, and ACD measurements were made with Pentacam topography at 0, 2, and 4 h in all groups. Magnesium (mg), sodium (Na), and chlorine (Cl) were measured in the blood at 0 and 2 h, and in blood, vitreous fluid, and humor aqueous at 4 h. Results: It was determined that CT, CV, ACV, and ACD are not of great value in drowning diagnosis and are affected by the fresh or salt water rather than drowning. Vitreous Na, Cl, and Mg levels are ineffective in determining drowning after one h. Anterior chamber fluid may provide valuable information in the differentiation freshwater - saltwater drownings at the 4th h in corpses retrieved from water. Conclusion: Anterior chamber fluid Na and Cl levels, especially in corpses removed from salt water, can be an easily used test that can help diagnose drowning.

The effect of underwater massage during hot water immersion on acute cardiovascular and mood responses.

PURPOSE: There is emerging evidence that demonstrates the health benefits of hot water immersion including improvements to cardiovascular health and reductions in stress and anxiety. Many commercially available hot tubs offer underwater massage systems which purport to enhance many benefits of hot water immersion, however, these claims have yet to be studied. METHODS: Twenty participants (4 females) completed three, 30-min sessions of hot-water immersion (beginning at 39 °C) in a crossover randomized design: with air massage (Air Jet), water massage (Hydro Jet) or no massage (Control). Cardiovascular responses comprising; heart rate, blood pressure and superficial femoral artery blood flow and shear rate were measured. State trait anxiety, basic affect, and salivary cortisol were recorded before and after each trial. Data were analysed using a mixed effects model. RESULTS: Post immersion, heart rate increased (Δ31bpm, P < 0.001, d = 1.38), mean arterial blood pressure decreased (Δ16 mmHg, P < 0.001, d = -0.66), with no difference between conditions. Blood flow and mean shear rate increased following immersion (P < 0.001, Δ362 ml/min, d = 1.20 and Δ108 s-1, d = 1.00), but these increases were blunted in the Air Jet condition (P < 0.001,Δ171 ml/min, d = 0.43 and Δ52 s-1, d = 0.52). Anxiety and salivary cortisol were reduced (P = 0.003, d = -0.20, P = 0.014, d = -0.11), but did not vary between conditions. Enjoyment did not vary between conditions. CONCLUSION: These data demonstrate positive acute responses to hot water immersion on markers of cardiovascular function, anxiety, and stress. There was no additional benefit of water-based massage, while air-based massage blunted some positive vascular responses due to lower heat conservation of the water.

The association between waterbirth and perineal injury or other adverse outcomes among low-risk women with physiological birth: Results from the Nordic Home Birth Cohort Study.

PROBLEM/BACKGROUND: Immersion in water has known benefits, such as reducing pain and shortening the duration of labour. The relationship between waterbirth and perineal injury remains unclear. AIM: To compare the incidence of perineal injury in waterbirth and birth on land among low-risk women. Secondary outcomes were postpartum haemorrhage and 5-minute Apgar scores <7. METHODS: Prospective cohort study of 2875 low-risk women who planned a home birth in Denmark, Iceland, Norway, and Sweden in 2008-2013 and had a spontaneous vaginal birth without intervention. Descriptive statistics and logistic regression were performed. FINDINGS: A total of 942 women had a waterbirth, and 1933 gave birth on land. The groups differed in their various background variables. Multiparous women had moderately lower rates of intact perineum (59.3% vs. 63.9%) and primiparous women had lower rates of episiotomies (1.1% vs. 4.8%) in waterbirth than in birth on land. No statistically significant differences were detected in adjusted regression analysis on intact perineum in waterbirth (primiparous women's aOR = 1.03, CI 0.68-1.58; multiparous women's aOR = 0.84, CI 0.67-1.05). The rates of sphincter injuries (0.9% vs. 0.6%) were low in both groups. No significant differences were detected in secondary outcomes. DISCUSSION: The decreased incidence of intact perineum among multiparous women was modest and inconclusive, and the prevalence of sphincter injury was low. CONCLUSION: Low-risk women contemplating waterbirth should be advised to weigh the risks and benefits detected in this study against previously established benefits of waterbirth and should make an informed choice based on their values.

Behavioral and electrophysiological study in Colossoma macropomum treated with different concentrations of Nepeta cataria oil in an immersion bath revealed a therapeutic window for anesthesia.

The purpose of this study was to characterize the activity of essential oils from Nepeta Cataria (EON) at concentrations of 125 µ L  L-1, 150 µ L  L-1, 175 µ L  L-1, and 200 µ L  L-1 on the behavior of loss of the posture reflex and recovery of the posture reflex and electrocardiographic activity and recording of the opercular beat of Colossoma macropomum during immersion bathing for a period of 5 min, in order to obtain a window for safe use during anesthesia. The fish (23.38 ± 3.5 g) were assigned to the following experiments: experiment 1 (latency to loss and recovery of the posture reflex): (a) 125 µ L  L-1, (b) 150 µ L  L-1, (c) 175 µ L  L-1, and (d) 200 µ L  L-1 (n = 9) per group. Experiment 2 (electrocardiographic and heartbeat recordings): (a) control group; (b) vehicle control group (2 ml of alcohol per liter of water), (c) 125 µ L  L-1, (d) 150 µ L  L-1, (e) 175 µ L  L-1, and (f) 200 µ L  L-1 (n = 9), per group. All the concentrations used showed efficacy in inducing loss of the posture reflex and reversibility with recovery of the posture reflex, but the electrocardiographic recordings indicated morphographic changes such as bradycardia during induction and p wave apiculation during recovery at the highest concentrations tested. In this way, we suggest a safe use window for short-term anesthesia with EON in the concentration range of 125 to 150 µ L  L-1 for juvenile Colossoma macropomum.

Redox profile of silver catfish challenged with Aeromonas hydrophila and treated with hexane extract of Hesperozygis ringens (Benth.) Epling through immersion bath.

The growing increase in the fish farming sector has favored the establishment of bacterial outbreaks caused by Aeromonas hydrophila in several species. The hexane extract of Hesperozygis ringens (HEHR) (Lamiaceae) leaves increased the survival rate of silver catfish (Rhamdia quelen) experimentally infected by A. hydrophila. However, it is noteworthy that no reports have been found on the possible mechanisms of action of this extract in infected fish. This study aimed to evaluate the effect of the HEHR, administered through single immersion bath, on lipid peroxidation and antioxidant defenses in muscle and liver tissue of silver catfish challenged with A. hydrophila. The results showed that the oxidative status of silver catfish was altered, although oxidative stress was not triggered during the experiment. HEHR at 30 mg/L (HEHR30) was not characterized as a pro-oxidant agent in the presence of infection, unlike florfenicol and HEHR at 15 mg/L treatments in some cases. In short, HEHR30 provided an important increase in hepatic catalase activity, characterizing one of the possible mechanisms involved in the greater survival of fish experimentally infected by A. hydrophila. Additionally, HEHR30 did not induce lipid peroxidation, nor reduced antioxidant defenses of silver catfish infected or not by A. hydrophila.

Effect of a single immersion in cold water below 4 °C on haemorheological properties of blood in healthy men.

Cold water immersion (CWI) involves rapid cooling of the body, which, in healthy individuals, triggers a defence response to an extreme stimulus, to which the body reacts with stress. The aim of the study was to determine the effect of CWI on hemorheological blood indicators. The study group consisted of 13 young males. Blood samples were collected before and after CWI. The assessed parameters included the complete blood count, fibrinogen, hs-C-reactive protein (CRP), proteinogram, and blood rheology factors, such as erythrocyte elongation index (EI), half-time of total aggregation, and aggregation index. Additionally, the effect of reduced temperature on primary human vascular endothelium was investigated in vitro. CWI resulted in the decrease of body temperature to 31.55 ± 2.87 °C. After CWI, neutrophil count and mean corpuscular volume (MCV) were significantly increased in the study group, while lymphocyte count was significantly decreased. Significantly higher levels of total blood protein and albumin concentration were detected after the immersion. Among hemorheological characteristics, erythrocyte EIs at shear stress values ranging from 2.19 to 60.30 Pa were significantly lower after CWI. No significant changes in other rheological, morphological or biochemical parameters were observed. In vitro, human umbilical vein endothelial cells responded to 3 h of temperature decrease to 25 °C with unchanged viability, but increased recruitment of THP-1 monocytic cells and changes in cell morphology were observed. This was the first study to evaluate the effect of single CWI on rheological properties of blood in healthy young men. The results indicate that a single CWI may increase blood protein concentrations and worsen erythrocyte deformability parameters.

Health Care Innovation for Low-Resource Settings: The Value of Local Immersion and Partnership.

Health Care Innovation is the creation, development, and translation of new and better solutions to health care challenges. At its core, this endeavor does not require extending the frontiers of science or the creation of new fundamental technologies. Rather, it is primarily focused on the use of existing science and established technologies in the design of new solutions to problems in health care. Successfully innovating for low- and middle-income countries (LMICs) requires a needs and stakeholder-driven approach to enable development and adoption of available, accessible, and acceptable solutions tailored to the specific need and context of care.

The interprofessional practice experiences of final-semester prelicensure BSN students completing clinical immersion: A descriptive qualitative study.

BACKGROUND: The goal of interprofessional practice experiences in health professions programs is to develop interprofessional collaborative practice skills. PURPOSE: The purpose of the study was to explore the meaning final-semester Bachelor of Science in Nursing students attributed to interprofessional practice experiences during clinical immersion. METHODS: The theoretical framework for this descriptive qualitative study was experiential learning theory. A sample of 12 participants was drawn from final-semester prelicensure Bachelor of Science in Nursing students at a college of nursing at a public research university. Data were collected through one-on-one semi-structured interviews and analyzed through inductive thematic analysis. RESULTS: The analysis yielded four themes: professional and interprofessional identity, working with team members, communication practices, and trusting relationships. Patterns across themes were clinical environment culture, nursing school preparation, nurse preceptor role, fear/concern/worry, and night shift. CONCLUSION: Consistency in preceptors, welcoming clinical environments, and opportunities to practice communicating with team members contributed to interprofessional collaborative practice skill development and improved perceptions of readiness for practice. Academic and clinical educators may use findings to (a) identify immersion placements for interprofessional practice experiences, (b) design curricula reflective of interprofessional practice, (c) advance teaching strategies to promote interprofessional practice, and (d) create learning environments that aid in professional and interprofessional identity formation.

The effects of cold exposure (cold water immersion, whole- and partial- body cryostimulation) on cardiovascular and cardiac autonomic control responses in healthy individuals: A systematic review, meta-analysis and meta-regression.

BACKGROUND: Cryostimulation and cold-water immersion (CWI) have recently gained widespread attention due to their association with changes in cardiovascular and cardiac autonomic control responses. Therefore, the aim of the present systematic review and meta-analysis was to identify the global impact of such cold exposures on cardiovascular and cardiac autonomic activity. METHODS: Three databases (PubMed, Embase, Web-of-Science) were used. Studies were eligible for inclusion if they were conducted on healthy participants using cryostimulation and/or CWI. The outcomes included measurements of blood pressure (BP), heart rate (HR), and heart rate variability (HRV) indices: RR interval (RR), Root mean square of successive RR interval differences (RMSSD), low frequency band (LF), high frequency band (HF), and LF/HF ratio. RESULTS: Among the 27 articles included in our systematic literature review, only 24 were incorporated into the meta-analysis. Our results reveal a significant increase in HRV indices: RMSSD (Standardized mean difference (SMD) = 0.61, p < 0.001), RR (SMD = 0.77, p < 0.001), and HF (SMD = 0.46, p < 0.001), as well as significantly reduced LF (SMD = -0.41, p < 0.001) and LF/HF ratio (SMD = -0.25, p < 0.01), which persisted up to 15 min following cold exposure. Significantly decreased heart rate (SMD = -0.16, p < 0.05), accompanied by slightly increased mean BP (SMD = 0.28, p < 0.001), was also observed. These results seem to depend on individual characteristics and the cooling techniques. CONCLUSION: Our meta-analysis suggests that cryostimulation and/or CWI exposure enhance parasympathetic nervous activity. There is scarce scientific literature regarding the effect of individual characteristics on cold-induced physiological responses.

Acute moderate normobaric hypoxia does not modify circulating thyroid hormone concentrations induced by 1 h of head-out cold-water immersion.

This study tested the hypothesis that acute moderate normobaric hypoxia augments circulating thyroid hormone concentrations during and following 1 h of cold head-out water immersion (HOWI), compared with when cold HOWI is completed during normobaric normoxia. In a randomized crossover single-blind design, 12 healthy adults (27 ± 2 yr, 2 women) completed 1 h of cold (22.0 ± 0.1°C) HOWI breathing either normobaric normoxia ([Formula: see text] = 0.21) or normobaric hypoxia ([Formula: see text] = 0.14). Free and total thyroxine (T3) and triiodothyronine (T4), and thyroid-stimulating hormone (TSH) concentrations were measured in venous blood samples obtained before (baseline), during (15-, 30-, and 60 min), and 15 min following HOWI (post-), and were corrected for changes in plasma volume. Arterial oxyhemoglobin saturation and core (rectal) temperature were measured continuously. Arterial oxyhemoglobin saturation was lower during hypoxia (90 ± 3%) compared with normoxia (98 ± 1%, P < 0.001). Core temperature fell from baseline (normoxia: 37.2 ± 0.4°C, hypoxia: 37.2 ± 0.4°C) to post-cold HOWI (normoxia: 36.4 ± 0.5°C, hypoxia: 36.3 ± 0.5°C, P < 0.001) in both conditions but did not change differently between conditions (condition × time: P = 0.552). Circulating TSH, total T3, free T4, total T3, and free T4 concentrations demonstrated significant main effects of time (all P ≤ 0.024), but these changes did not differ between normoxic and hypoxic conditions (condition × time: all P ≥ 0.163). These data indicate that acute moderate normobaric hypoxia does not modify the circulating thyroid hormone response during 1 h of cold HOWI.NEW & NOTEWORTHY Acute head-out cold (22°C) water immersion (HOWI) decreased core temperature and increased thermogenesis. This thermogenic response was paralleled by the activation of the hypothalamic-pituitary-thyroid axis, as evidenced by changes in thyroid hormones. However, cold HOWI in combination with moderate normobaric hypoxia did not modify the thermogenic nor the circulating thyroid hormone response. This finding suggests that hypoxia-induced alterations in thyroid hormone concentrations are unlikely to acutely contribute to adaptations resulting from repeated cold-water exposures.

Does dietary total antioxidant capacity relate to oxidative stress levels in water immersion during labor? A case-control study.

OBJECTIVE: The aim of this study was to investigate the effect of water immersion during the first stage of labor on maternal and neonatal oxidative stress and the association between serum and dietary total antioxidant capacity. METHODS: Women were divided into two groups: those immersed in water during the first stage of labor (n=30) and those who had conventional birth (n=33). Total oxidative stress and total antioxidant status levels were examined in antepartum and postpartum maternal serum and neonatal cord blood samples. Dietary total antioxidant capacity was determined by the food frequency questionnaire. RESULTS: Vitamin C and dietary total antioxidant capacity consumption were found to be higher in the water immersion group (106.92 mg/day and 18.94 mmol/gün, respectively) than the conventional birth group (92.69 mg/day and 15.99 mmol/gün, respectively) (p<0.05). Women immersed in water during the first stage of labor had lower total oxidative stress levels in antepartum and postpartum maternal serum and neonatal cord blood samples than those who had conventional birth (5.43±2.42 mmol/L and 5.59±3.35 mmol/L vs. 8.58±5.53 mmol/L and 12.68±16.58 mmol/L; p<0.05). Dietary total antioxidant capacity was found to be negatively correlated with total oxidative stress levels in antepartum and postpartum maternal serum and neonatal cord blood samples (p=0.012, p=0.047, p=0.035, and p<0.05). CONCLUSION: Women immersed in water during the first stage of labor had lower total oxidative stress levels in their postnatal maternal serum and neonatal cord blood samples and dietary total antioxidant capacity was also a factor associated with low total oxidative stress levels.

Combined cold-water immersion and breathwork may be associated with improved mental health and reduction in the duration of upper respiratory tract infection - a case-control study.

A polar plunge is a term referring to an ice-cold water immersion (CWI), usually in the winter period. It is also a part of a specific training program (STP) which currently gains popularity worldwide and was proven to display paradigm-shifting characteristics. The aim of this study was to compare the indices of mental functioning (including depression, anxiety, mindfulness) and duration of upper respiratory tract infection (URTI) measured among the study participants. A set of questionnaires was distributed via the Internet. Participants declaring regular STP practice were selected (N = 77). Two groups were matched based on a case-control principle: the first one (the control group) comprised participants who did not declare nor CWI practice, nor STP practice. The second one comprised participants declaring regular CWI practice only. The CWI only group displayed better mental health indices and shorter URTIs compared to the control group. Moreover, the STP group also displayed better general mental health, less somatic complaints, and shorter URTIs compared to the CWI only group. This study suggests the existence of CWI's potential in boosting mental health and immune system functioning, however when complemented by a specific breathwork, this potential can be increased. However, further research is required.

Mannose modified targeted immersion vaccine delivery system improves protective immunity against Infectious spleen and kidney necrosis virus in mandarin fish (Siniperca chuatsi).

Vaccination is an effective method to prevent viral diseases. However, the biological barrier prevents the immersion vaccine from achieving the best effect without adding adjuvants and carriers. Researches on the targeted presentation technology of vaccines with nanocarriers are helpful to develop immersion vaccines for fish that can break through biological barriers and play an effective role in fish defense. In our study, functionally modified single-walled carbon nanotubes (SWCNTs) were used as carriers to construct a targeted immersion vaccine (SWCNTs-M-MCP) with mannose modified major capsid protein (MCP) to target antigen-presenting cells (APCs), against iridovirus diseases. After bath immunization, our results showed that SWCNTs-M-MCP induced the presentation process and uptake of APCs, triggering a powerful immune response. Moreover, the highest relative percent survival (RPS) was 81.3% in SWCNTs-M-MCP group, which was only 41.5% in SWCNTs-MCP group. Altogether, this study indicates that the SWCNTs-based targeted immersion vaccine induces strong immune response and provided an effective protection against iridovirus diseases.

Post exercise hot water immersion and hot water immersion in isolation enhance vascular, blood marker, and perceptual responses when compared to exercise alone.

Exercise and passive heating induce some similar vascular hemodynamic, circulating blood marker, and perceptual responses. However, it remains unknown whether post exercise hot water immersion can synergise exercise derived responses and if they differ from hot water immersion alone. This study investigated the acute responses to post moderate-intensity exercise hot water immersion (EX+HWI) when compared to exercise (EX+REST) and hot water immersion (HWI+HWI) alone. Sixteen physically inactive middle-aged adults (nine males and seven females) completed a randomized cross-over counterbalanced design. Each condition consisted of two 30-min bouts separated by 10 min of rest. Cycling was set at a power output equivalent to 50% V̇o2 peak . Water temperature was controlled at 40°C up to the mid sternum with arms not submerged. Venous blood samples and artery ultrasound scans were assessed at 0 (baseline), 30 (immediately post stressor one), 70 (immediately post stressor two), and 100 min (recovery). Additional physiological and perceptual measures were assessed at 10-min intervals. Brachial and superficial femoral artery shear rates were higher after EX+HWI and HWI+HWI when compared with EX+REST (p < 0.001). Plasma nitrite was higher immediately following EX+HWI and HWI+HWI than EX+REST (p < 0.01). Serum interleukin-6 was higher immediately after EX+HWI compared to EX+REST (p = 0.046). Serum cortisol was lower at 30 min in the HWI+HWI condition in contrast to EX+REST (p = 0.026). EX+HWI and HWI+HWI were more enjoyable than EX+REST (p < 0.05). Irrespective of whether hot water immersion proceeded exercise or heating, hot water immersion enhanced vascular and blood marker responses, while also being more enjoyable than exercise alone.