Tired all day from work and mentally drained: what can I do?

Feeling worn out by mid-afternoon, and too drained to think clearly by the evening, is common when work is heavy. It rarely has a single cause. Short sleep, long stretches at a screen without a break, skipped or late meals, too little water and sitting all day tend to stack up. The things to look at first are sleep, short regular breaks, regular meals and water, and when you have caffeine. If you have felt tired for weeks without knowing why, see a doctor.

In Bangkok and other Thai cities, a heavy workday often starts with an early commute on the BTS or in traffic, runs through back-to-back meetings and chat messages, and ends with overtime or a late dinner. Each of these on its own is manageable. Together, day after day, they leave little time for rest.

Why am I tired all day when work is heavy?

The UK's NHS says many cases of tiredness are due to stress, not enough sleep, poor diet and other lifestyle factors. The UK's Health and Safety Executive (HSE) adds that long working hours that do not balance the demands of work with time for rest and recovery can result in fatigue.

Common reasons on heavy workdays

Short sleep that adds up

The US CDC says adults aged 18 to 60 need 7 or more hours of sleep. If overtime, a late dinner and scrolling on your phone push bedtime past midnight and the alarm still goes off at six, the shortfall grows every workday.

Meals that drift

On busy days, breakfast becomes a coffee on the way in, lunch is eaten at the desk or skipped, and dinner arrives late and large. The NHS suggests eating regular meals and healthy snacks every 3 to 4 hours, rather than a large meal less often.

Why does my brain feel drained after a day of meetings and screens?

The HSE describes fatigue as a decline in mental and/or physical performance that results from prolonged exertion, sleep loss and/or disruption of the internal clock. The effects it lists include slower reactions, reduced ability to process information, memory lapses and absent-mindedness. Many people know this as the feeling that a simple email takes three tries to write at 5 p.m.

Hours of screen work without moving

Screen work keeps your eyes, attention and posture fixed in one place for a long time. When one call runs straight into the next and lunch is eaten in front of the laptop, there is no point in the day when you actually stop.

Messages that never switch off

Chat groups and email that keep arriving after hours mean work does not really end when you leave the office. The HSE's point about time for rest and recovery applies to evenings too.

What can I do during the workday?

Take short breaks often

The HSE suggests taking short breaks often, rather than longer ones less often. For example, 5 to 10 minutes every hour is better than 20 minutes every 2 hours. Breaks should let you get up from your desk and move around, or at least stretch and change posture. The HSE notes there is no legal rule on exactly how long or how often.

Move a little

The NHS says even a single 15-minute walk can leave you feeling more energetic. A walk to a food stall for lunch, taking the stairs, or getting off one BTS stop early all count. The NHS physical activity guidelines suggest at least 150 minutes of moderate intensity activity a week, and breaking up long periods of not moving with some activity.

Keep water within reach

The NHS says that sometimes you feel tired simply because you are mildly dehydrated, and suggests a glass of water, especially after exercise. In an air-conditioned office it is easy to forget to drink, and then to step out into the afternoon heat.

How should I eat and drink on heavy workdays?

Regular meals instead of one big one

The NHS suggests eating regular meals and healthy snacks every 3 to 4 hours, rather than a large meal less often. If lunch is often late, a small snack such as fruit, yoghurt or a handful of nuts in the late morning can keep the gap shorter. Many people feel sleepy after a big plate of rice at lunch followed by a sweet drink.

Drink enough fluids

The NHS says the UK government recommends aiming for 6 to 8 cups or glasses of fluid a day, and that you may need more in a hot environment or if you are physically active for long periods. Water, lower-fat milk and lower-sugar drinks, including tea and coffee, all count.

Coffee: how much and until when

The US FDA gives the 400 mg figure as an amount not generally associated with negative effects. A large iced coffee in the morning, a Thai tea after lunch and an energy drink at 4 p.m. can add up quickly, and the late ones can cut into that night's sleep. If you want to cut down, the NHS suggests doing it gradually rather than stopping suddenly.

What should I do after work and before bed?

Protect your sleep hours

The NHS suggests going to bed and getting up at the same time every day, taking time to relax before bed, and avoiding naps in the day. Aim for the 7 or more hours the CDC gives for adults. If you work late, setting a time after which you stop checking work messages helps the evening become rest time.

Weekends

The NHS suggests getting up at the same time every day. On days off, try to wake up close to your weekday time and spend some time outdoors in daylight.

When is work tiredness worth seeing a doctor about?

The NHS advises seeing a doctor if:

• you have felt tired for a few weeks and are not sure why
• tiredness affects your daily life
• you feel tired and have other symptoms, such as weight loss or mood changes

Note these down before your appointment

• your usual working hours, including overtime, over the past two to four weeks
• when you went to sleep and woke up each day
• how much coffee, tea and energy drinks you have each day
• all the medicines and supplements you take
• anything else you have noticed, such as weight or mood changes

This helps the doctor see the full picture.

Before starting a supplement or medicine

If you take regular medicines, are pregnant, or are not sure something suits you, talk to a doctor or pharmacist before you start taking anything new. Don't start any medicine on your own.