Written by Caroline Donovan, CORU Registered Dietitian with the Irish Heart Foundation BSc., MSc., Pg. Dip.
Water and heart health
Water is the main constituent of the body, accounting for 50-60% of body weight in adults. In infants, it is suggested that 75% of body weight is accounted for by water, while this reduces to 55% in older adults. Given that water is also the largest component of our hearts, it is unsurprising that adequate water in-take is key to maintaining heart health. Adequate intake is essential for many bodily functions, but with regard to the heart it is essential in helping the heart pump efficiently, supporting blood vessel function, and in maintaining healthy circulation. Staying well hydrated allows these functions to work optimally.
In the longer term, staying hydrated has been associated with a reduced risk of developing heart failure. Consuming sufficient amounts of fluids throughout the life course not only supports essential body functioning but may also reduce the risk of severe heart problems in older age. Cardiovascular disease mortality risk has been found to be lower among those who consume adequate amounts of water regularly. Water is therefore considered an essential component of dietary intakes given that only a small amount of water (~250ml/day) is produced through metabolism.
Recently, drinking water and staying hydrated has been trending, thanks to the wellness industry. Influencers have helped the cause of water intakes with a rise among influencers promoting branded, affiliated reusable water bottles and #hydration trending across social media platforms, with challenges and trends aiming to increase hydration status. Glamorizing humble hydration is most certainly a trend to be welcomed.
The focus of this article is for those who are generally well and wish to maintain optimum health, particularly heart health. Those with acute or chronic conditions may have individualised fluid requirements, and certain medications may also dictate such requirements. These are therefore beyond the scope of this article and require individualised fluid requirements.
Dehydration and heart rate –how does dehydration affect heart and health?
The sensation of feeling thirsty is the body’s way of letting us know that we are dehydrated. However, often by the time we feel the sensation of thirst the body may already be dehydrated. Dehydration occurs when inadequate amounts of fluids are either consumed, or are lost and not replaced. Water is lost by way of bodily excretion through urine, sweat, faeces, evaporation through respiration and is lost through the skin. Dehydration can impair mental and physical performance, causing tiredness and poor concentration levels but may also have a negative impact on cardiovascular health. Cardiovascular function is impaired when the body is dehydrated, whereby heart rate increases, and blood pressure decreases more rapidly than when the body is adequately hydrated. It has been found that prolonged states of dehydration may reduce endothelial function, increase sympathetic nervous system activity, and worsen orthostatic tolerance. Ultimately, these negative impacts cause the heart to work harder, compensating by beating faster and hence increasing stress on the heart.
Those at greatest risk of dehydration are babies and infants, older adults, people with long-term health conditions such as diabetes and kidney disease, and athletes. Adequate hydration status is also important while pregnant and breastfeeding.
How much water do you need?
According to the current guidelines in Ireland, women and teenage girls should aim to consume 2 liters of water daily, while men and teenage boys should aim for 2.5 liters. This equates to between 8-10 200ml cups of water per day. It is advised to drink plenty of fluids throughout the day, with water recommended as the best option as it replaces fluids lost without increasing caloric intake. While these are general recommendations, various factors can impact on our fluid requirements.
Factors that influence your water needs
Fluid requirements vary depending on factors including age, weight, levels of physical activity and environmental factors such as extreme heat. Requirements are estimated based on average body weight; therefore, children require less fluid than adults. Due to the increased period of growth and activity experienced in adolescent years, fluid requirements for teenagers are the same as those for adults to compensate for natural losses. Levels of physical activity also influence fluid requirements. This is especially relevant to those undertaking regular vigorous physical activity as their requirements will be greater given losses through sweating.
Tips for increasing your water intake
Paying attention to the colour of your urine is one of the easiest ways to assess one’s own hydration status. Good hydration is indicated by a pale clear straw yellow colour urine, while darker colour urine indicates poor hydration and is a sign that more fluids should be consumed.
Steadily consuming water throughout the day is the single best way to increase hydration status. Fruit and vegetables are also considered a source of water. Increasing your intake can help to improve your hydration status while also meeting the dietary requirements of 5-7 servings of fruit and vegetables per day. Although other drinks such as milk, fruit juice, tea and coffee also contribute to fluid intakes, water is considered the most preferable choice.
Here are some tips for increasing daily water intake:
• Having a reusable water bottle is a good way to both encourage water intake throughout the day and help you to become conscious of your overall water intake.
• Build drinking water into your daily routine, be this at work, in meetings, while travelling or with meals.
• Add fruits to add flavor if you find drinking plain water difficult.
• If you choose to add squashes or a dilutable ensure these are sugar-free.
• If you prefer chilled water, make sure to keep a jug of water in the fridge or freeze your water bottle overnight, or simply add some ice cubes to keep your water chilled.
• Swap one tea or coffee to water to increase your water intake. Although caffeinated drinks count towards overall fluid intakes, swapping one to plain water would help to improve water intake.
• Throughout the day, aim for water to be the main fluid you are consuming.
For more information on water and your heart health, visit irishheart.ie
