Are foreign condoms safe to use? Is sex in the ocean bad for you? Dr Sarah Brewer answers your burning questions about holiday fun and sun

If you are planning a holiday of sun, sand, super fun and sex this year, here's a health Q&A to work through to help keep problems to a minimum.

Even if you think your holiday will just be sun and sand with no sex, it's still worth taking precautions for your sexual health and well-being. Pack a few condoms 'just in case' as it's better to be safe than sorry. Foreign condoms - especially the fundom versions with glow-in-the-dark, go-faster stripes - cannot always be relied on to protect against STIs or pregnancy; especially with the rigours of active holiday sex.

Can having sex in salt water irritate tender tissues?
Salt water has a similar strength to body tissues, so you shouldn't find it too uncomfortable having sex in the sea. If there's lots of sand suspended in the water, however, friction may cause discomfort. Bear in mind that some countries have strict regulations about sex in public places, so check by-laws and ensure total privacy if you don't want to spend your holiday in the local clink.

Can sex in the sand cause the equivalent of rug burns?
Sand can easily be introduced into the vagina during sex on the beach which can lead to irritation and soreness. Lying on a large beach towel may help overcome this problem. A good shower afterwards will usually sort things out, but avoid douching - the vagina has excellent self-cleaning mechanisms and stray grains of sand will soon work their way out.

Does sun cream weaken condoms?
Don't use sun cream as a lubricant as oil-based products (including baby oil, petroleum jelly, butter, some spermicidal creams) weaken and dissolve latex rubber - some have been shown to reduce condom strength by up to 95 per cent within 15 minutes. Only use a water-based lubricant specifically designed for use with latex condoms, or buy the more expensive polyurethane versions. It's also a good idea to consider selecting condoms that are pre-lubricated with spermicide for extra protection. Condoms that are used too dry will reduce sensitivity for both partners and are also more likely to tear during use.

Why does alcohol lower my inhibitions?
Alcohol is a sedative, and has a depressant action on the central nervous system and damps down your usual protective psychological and social inhibitions. Although this may make you feel euphoric and dynamic, it will affect your judgement, even on things like deciding when you've been in the sun too long, whether you are drinking enough water, as well as common sense decisions on sex issues. And on top of that, in small quantities, alcohol is an aphrodisiac - but only for women, it seems. After drinking two units of alcohol, female testosterone levels rise one to two hours later. In larger quantities, however, alcohol lowers oestrogen and testosterone levels so you may feel less sexy as the night wears on.

Is it true that nude sunbathing weakens breast tissues?
Sensible sun exposure is unlikely to damage breast tissue any more than other parts. Nipples and white breasts are very prone to burning however, so make sure you slather on the sun cream, don't bare your all for too long and only gradually increase daily exposure times. Check local regulations regarding the acceptability of nude sunbathing, too.

Which countries have the worst problems with STIs?
All countries have problems with sexually transmissible infections - in the UK for example, our rates of infection are increasing every year. While statistics from some countries in Africa suggest that over ten per cent of the population are living with HIV, it is estimated that more than two million people in Europe are HIV positive. You can check some of the statistics at the following site: http://www.avert.org/statindx.htm. It is safest to assume that any person you meet on holiday is a potential source of infection with genital warts, herpes, Chlamydia, gonorrhoea, syphilis or HIV, for example. If you still want to have sex with them, always use a condom.

Is foreign contraception reliable?
Different countries often have different standards sizes for condom width - in Singapore for example, they are usually 52mm in width, but only 49mm in Thailand. If you and your partner are going on holiday together and use condoms, take more than you think you will need with you as you may not be able to get your normal size abroad. Condoms in different countries will also be made to varying safety standards. Condoms can never offer 100 per cent safety, but used properly, they are very reliable and give good protection against pregnancy and STIs - only use condoms bearing marks from ISO (International Standards Organisation), the European CEN or the American ASTM. Check packagings of 'fundoms' for small print which often states 'Not to be used as a barrier'. And don't forget to pack your contraceptive pills and any other regular medication you might need.

What about foreign healthcare?
Whenever planning a trip abroad, check which vaccinations you will need two to three months in advance so you have plenty of time to fit them in and get them protecting you before you go. A free leaflet, Health Advice for Travellers is available by phoning the Health Literature Line on 0800 555 777. You can also visit www.travelhealth.co.uk and www.masta.org for information. Always take a basic first-aid kit with you to cope with minor illnesses, and ensure you have holiday health insurance in place in case you need to seek medical care abroad. Your hotel can usually recommend a local doctor if you need an urgent appointment.